Summary
Back at the Duke's camp, Parolles is "captured" by a company pretending to be enemy soldiers. To confuse Parolles, they speak a nonsense language and even designate one person to be their "interpreter."
Meanwhile, Diana tells Bertram that she will sleep with him if he gives her his ring as a token of his love. He agrees after some hesitation, telling her that the ring is a family heirloom. Diana gives Bertram a ring of her own, which is actually Helena's ring, given to her by the King as a token of his appreciation after his recovery.
At camp, the Countess's letter has arrived, along with the news that Helena has died in the monastery (a rumor likely spread by Helena herself).
Bertram arrives after his tryst with Diana (in actuality, Helena) and the brothers Dumaine lead him to where Parolles is being held captive. They threaten him with torture if he does not reveal everything about the army, and he willingly gives up information while speaking ill of Bertram and the Dumaines. When they threaten to kill him, Parolles begs for his life. They remove his blindfold and reveal the ruse, leaving Parolles embarrassed and friendless.
The war eventually ends with a truce, and Bertram plans to return home (believing his wife to be dead).
Helena asks the Widow and Diana to travel with her to Marseilles, where the King's court is now located.
Lafeu suggests to the Countess that Bertram marry his daughter (because, once again, everyone believes Helena is dead), and the Countess agrees.
Analysis
Act Four focuses largely on the exposure of Parolles as a cowardly traitor.
In the earliest editions of the play, this plot surrounding Parolles was markedly less prominent. However, the play was edited extensively to include more time on stage for Parolles, whom many see as an early incarnation (or perhaps contemporary spin-off) of a Shakespearean fan favorite, Sir John Falstaff. Falstaff was a recurring character in Shakespeare's Henriad plays, and even inspired his own comedic spin-off in The Merry Wives of Windsor. A boisterous, fat, thieving knight who served as the companion to Prince Hal before he became Henry V, Falstaff was beloved by early modern audiences for his less-than-honorable demeanor.
However, part of Falstaff's charm was also his self-awareness and unparalleled wit; he was a scoundrel, but a clever scoundrel who often spoke uncomfortable truths about the nature of men, power, and history. By contrast, Parolles does not exhibit this same wisdom or cleverness as Falstaff; his boastful-turned-cowardly behavior only serves to emphasize his duplicitous nature, rendering him more of a villain in the play than a lovable buffoon. For most critics, Parolles's unredeemable character is one of the greatest drawbacks of the play.
Act Four also showcases how the scheming of the female characters plays out successfully, with Bertram being easily duped into sleeping with his wife, Helena.
The exchange of rings, an important symbol of loyalty and love in the play, offers a figurative "marriage" between Bertram and Helena through the vehicle of Diana, who pretends to love Bertram. That Bertram is not so willing to part with his ring – even for Diana, whom he purportedly loves – emphasizes his earlier refusal to become a husband and to be "bound" by the confines of marriage. Of course, the dramatic irony of the situation is that the rings he exchanges with Diana are representative of his already-existing marriage to Helena.
As such, the play dramatizes how the women of the play are seemingly always one step ahead of the men; Helena's cleverness plays out in her favor a she is able "marry" Bertram both in name, symbol, and body.
