In the early books of the Aeneid, Aeneas is portrayed as the son of gods (1.579), "handsome past all others" (4.190), and a valiant, loyal warrior. In his speech to Dido in Book 4, however, he is suddenly depicted in a far more negative light. In contrast to Dido's emotional outpouring, Aeneas appears evasive and cold, and he seems to imply that he is immune from censure.
After Dido accuses Aeneas of fleeing her land, Aeneas responds not in the strong, direct manner that has characterized his speech throughout Books 2 and 3, but in an evasive, almost dishonest fashion. Aeneas counters Dido's accusations by saying, "I never hoped to hide - do not imagine that - my flight; I am not furtive" (4.455-7), and yet Virgil himself has already passed judgment on Aeneas, writing that "Dido ... had caught his craftiness" (4.396-7). Even his speech is described as "struggl[ing]" (4.448) and "halting" (4.449) - not exactly the clear, direct tone of one who speaks the truth. In this speech, Virgil portrays Aeneas as an evasive man who counters Dido's direct, heartfelt speech with an unclear, even deceptive reply.
Aeneas's emotionless speech directly contrasts with Dido's impassioned plea. Whereas Dido cries, "Why do I live on?" (4.437), Aeneas responds by merely telling her that "I should cherish first the town of Troy" (4.462-63) and that "The Lycian prophecies tell me of Italy: there is my love" (4.469-70). Aeneas's cold-sober attitude towards Dido is far different than that which he displayed towards his first wife, Creusa, of whom he says that "fate tears from [him]" (2.994). In contrast to the loving manner in which Aeneas speaks of his deceased wife, and the passionate way in which Dido speaks of him, Aeneas here seems cold, detached, and almost cruel.
In his defense, the gods play a significant role, dictating his fate. Leave he must. In Aeneas's speech to Dido, he invokes his responsibility to the gods in order to exempt himself from responsibility for his hurtful actions, saying that "It is not/ my own free will that leads to Italy" (4.491-92). It is not his fault that he must leave her; he is merely following orders sent down "by the gods' own messenger" (4.484-85). Aeneas is not only arguing for Dido that he is not wrong to leave her - he is obeying divine directions at great cost - but he also seems to be assuaging his own guilt.
Any character sketch of Aeneas should come to terms with his treatment of Dido at this crucial juncture.