Chapter 23 opens with two letters. The first is from Tom to Mr. Greenleaf. Tom describes his last (fictional) interactions with Dickie in Rome, just after Freddie's death. He describes Dickie as shocked and upset, and regretfully muses that he may have committed suicide after his friend's murder. The second letter is from Marge to Tom, in reply to a letter he has just sent her. She argues that Dickie might have been killed by a stranger, but did not commit suicide. Marge agrees with Tom that the forgeries under investigation are likely not forgeries at all. She also informs him that Mr. Greenleaf will be coming to Rome, and that she will meet with him. Dickie's disappearance has become a huge news story lately. At parties in Venice, Tom is treated like a celebrity because of his association with Dickie, and the press routinely publishes articles theorizing about Dickie's whereabouts and describing him as a rebellious, unpredictable young man. Tom is flattered that the papers describe him as a "well-to-do American visitor" and that they characterize his new house in Venice as a "palazzo." The house is indeed luxurious and well-located, and Tom has put a great deal of effort into decorating it with antiques. In general he is feeling confident, so much so that he forges Dickie's will and places it in an envelope stipulating that it not be opened until June. Still, Tom suffers from the familiar sensation that he is being followed, and knows that the police need take only a short leap of the imagination to realize the truth. One day Marge calls Tom and tells him that she is in Venice. Tom invites her over. At his house she seems optimistic and convinced that Dickie is still alive. This irritates Tom, but he tries to appear generous and happy to see her. She tells Tom that Herbert Greenleaf is in Rome, and that the two of them have been speaking to all of Dickie's acquaintances, trying to find answers. She also asks Tom detailed questions about Dickie's state of mind before his disappearance and about Dickie's feelings for her. Tom tries to answer diplomatically, saying that Dickie was not able to commit to the idea of marriage. He also invites her to spend the night, even though he is repelled by the idea of having her in his house. He remembers seeing her bra hung out to dry at her house in Mongibello, and is viscerally upset by the thought that her underclothes might be visible in his own beloved home. Marge is excited by the prospect of a night in Venice, and Tom resolves to take her to his friend Peter's house in the evening to kill some time.
That night at Peter's, Tom gives Mr. Greenleaf a call in Rome. Greenleaf seems anxious but not angry with Tom, and casts doubt on the abilities of the Italian police. He turns down Tom's invitation to visit Venice. After the phone call, Tom reenters the room where Peter and Marge are socializing with two young Italian brothers, the Franchettis. One of the Franchettis jokes that Dickie probably has disguised himself by trading passports with a fisherman. Tom tries to casually argue that this isn't possible. Seeking more information, one of the Franchettis volunteers to grab the latest newspapers. Tom muses that Italians like the Franchettis always dress in English-made clothes, while Englishmen in Italy always wear Italian clothes. More guests arrive while they peruse the newspapers, which offer no useful information but are packed with speculation and even cartoons about Dickie's disappearance. Tom becomes nervous and annoyed with Marge, who has already agreed to attend a party the next day, thus implying that she will not be leaving Venice as soon as Tom would prefer. Marge wants to eat a long dinner after they leave, and to take a private gondola to Tom's house. However, the gondola drops them at the front door, to which Tom does not carry a key. They are unable to reach the other side of the house without another boat, due to Venice's system of canals. While eventually they find one, Tom's frustration with Marge is at a fever pitch by the time they get home.
The next day, Tom gets a telegram from Herbert Greenleaf announcing that he has changed his mind and intends to visit that day. Marge and Tom greet him at the train station later that morning, and the three go to a restaurant for lunch. Greenleaf is quiet and clearly distressed, and Tom gets the impression that he would like to speak privately, without Marge. Back at Tom's house, they do. Tom tells Mr. Greenleaf that Dickie might be hiding in Italy, since he could avoid showing his passport at a small hotel in a rural area. However, he repeats his previous claim that Dickie likely committed suicide, and that he acted strangely in Rome after Freddie's death. Greenleaf muses that he would like to find Dickie's mentor Di Massimo, but that he has been unable to do so, and suspects his son invented the painter. Tom also mentions the story of the San Remo boat, explaining that the police briefly suspected that Dickie had killed Tom himself on the boat. He does so knowing that the police are likely to mention the boat to Greenleaf eventually. He explains that Dickie avoided being questioned by the police about Tom's whereabouts (not mentioning, of course, that Dickie was in fact dead at the time), telling Mr. Greenleaf that this strange behavior makes it seem likely that Dickie killed himself. However, Mr. Greenleaf does not believe that his son committed suicide. Tom concedes that Dickie may simply be hiding elsewhere in Europe.
That night, after Mr. Greenleaf returns to his hotel, Marge insists on attending the cocktail party she had been invited to the night before. Tom is reluctant, knowing that he and Marge will be the center of attention there, but attends anyway. The party is at the home of an American traveler named Rudy Maloof, whom Tom finds uncultured and tiresome. He fantasizes about the solitary travel he will enjoy in June, after the "discovery" of Dickie's forged will. Seeing that Marge has become slightly drunk, and feeling uncontrollably angry with her, Tom forcibly steers her out of the party. He tells Marge that he has done so because he is upset by the sensational way the other guests discuss Dickie. Marge and Tom meet up with Mr. Greenleaf for drinks and dinner, and find Mr. Greenleaf in a better mood, because he has heard from his wife, who seems to be feeling well. He plans on returning to Rome in the morning, which is a relief to Tom. At home, Tom reads some letters from his old friend and housemate Bob. Bob says that someone has been using their house to receive checks as part of a tax fraud scheme. This doesn't worry Tom, since Bob's tone shows that he finds this slightly funny, and certainly does not believe that Tom bears any responsibility. Instead, Tom feels scornful of his friends in New York, and thinks that he may stay in Europe forever. He lovingly considers the possessions he has curated, thinking that Dickie's money has merely given him the ability to live according to his own refined taste. Tom is in a happy reverie when Marge enters, announcing that she has found Dickie's rings among his things. Tom quickly invents a lie. He says that Dickie gave him the rings in Rome, instructing him to keep watch over them in case anything happened to Dickie. While explaining this, Tom considers beating Marge to death with the heavy heel of his shoe. Marge seems to conclude that the story of Dickie's rings means he committed suicide. She leaves, dejected, to go to bed before Tom can hurt her. Tom feels horrified, realizing how easily he almost slipped from imagining violence to committing it. He is suddenly struck by the reality that he has killed multiple people. Calming himself, he imagines the story he will tell Mr. Greenleaf about the rings, becoming so engaged that he almost believes it himself.
Tom's sudden feeling of terror after Marge finds Dickie's rings goes well beyond fear of being found out. This is the first moment where we see Tom reckon, in a self-aware way, with the gravity of what he has done. What seems to frighten him most is how easily he slips from imagining to acting. His imagination is so vivid that it seems to function of its own accord, without any effort on his part. Once he envisions something vividly in his head, it feels almost inevitable for him to make the scenario a reality. Readers get a glimpse of this process while he considers the lie he will tell about Dickie's rings. While he hastily tells Marge that he was asked to keep them, he knows that he must appear more convincing for Mr. Greenleaf. In order to tell this lie conveniently, he must convince himself, using detailed imaginary scenes that show his conversation with Dickie. Just as he has managed to act like Dickie simply by making himself feel like Dickie, he is able to act as if Dickie has given him the rings simply by convincing himself that this occurred. Once again, readers see that Tom is very much an artist in some ways. While his "art" tends to result in a great deal of distress for others, there is no doubt that he is a gifted storyteller and actor. In fact, he tends to become so caught up in his own stories and performances that he loses control, experiencing the kind of artistic ecstasy that Dickie and Marge both seem to long for in their respective art forms. Tom's scorn for Marge has many sources and is expressed in many ways, but this may be one aspect of it—he knows that he can tell stories far better than she can. Of course, his ego and his emotional instability make it hard for him to see that murder may be too high a cost for artistic fulfillment.
One other way in which Tom expresses scorn for Marge is through misogynistic tropes. He is disgusted, above all, by the idea that she might leave her underclothes visibly strewn around his house. He also notes her "gourd-like figure" and sourly compares her to a girl scout. Readers are likely to feel that Marge is somewhat naive, possibly because she, like Dickie, comes from a privileged background. However, she isn't as stupid, childlike, or obnoxious as Tom seems to think. In fact, Marge seems fairly intelligent, and is quite kind and sociable. Tom, though, needs a justification for his dislike of Marge. Subconsciously, he finds her threatening because she was in love with Dickie, and once competed with him for Dickie. Marge even suspected Tom of being in love with Dickie as well, raising suspicions about Tom's sexuality. Furthermore, Marge was the only witness to most of Tom's interactions with Dickie, and is therefore somewhat uniquely positioned to discover the truth about Tom's actions. Misogyny gives Tom a convenient set of stereotypes with which to express this disgust, never admitting to himself the true reasons for his dislike. It is easier for Tom to acknowledge that he finds Marge ugly or unladylike than it is for him to acknowledge that he might get caught, or that he had feelings for another man. Tom's misogyny, much like his violence, seems to stem from personal pain. While Highsmith makes it clear that Marge has done little wrong (and that Tom has done a great deal wrong), she manages to simultaneously entangle readers in Tom's internal logic. Therefore, readers develop a kind of double-vision, at once understanding the strange workings of Tom's mind and understanding that Tom is detached from reality.
At times, the things that make Tom angry are genuinely upsetting. The Americans and Englishmen that Tom befriends in Italy, for instance, discuss the murders of Dickie and Freddie in bizarrely amused tones, as if unable to grasp the seriousness of the situation, or to comprehend that Marge and Tom might be upset about it. Tom, of course, is the killer of both men, and not a sensitive mourner. Still, his irritation towards men like Rudy Maloof feels reasonable. As a result, Highsmith puts readers in the strange position of sympathizing with Tom, and looking down on people guilty of causing far less harm. Many of Tom's acquaintances, such as Marge, appear to be genuinely good or at least well-meaning people. Yet some do not, and this infusion of somewhat unsavory figures makes Tom more likable by comparison.