Scene I: Leaving Dorimant's house in a chair at 5:00 a.m., Belinda arrives at Loveit's; however, Loveit knows the chair as the one she has taken from Dorimant's and becomes suspicious. Belinda lies about her whereabouts in order to save her reputation. But, when Dorimant is announced, she faints and is taken to Loveit's room. Mocking Sir Fopling as he enters, he meets criticism by Loveit; she and Dorimant accuse each other and exchange witticisms in Truewit fashion.
Loveit informs Dorimant she is aware that he feigns jealousy in order to give himself time with another while Dorimant accuses her of exchanging 'confidences ' with Sir Fopling. Loveit acts indifferently, but cannot let him go: "Equisite fiend! I know you came but to torment me." Belinda then enters, accusing Dorimant of villainies, and Loveit wants Dorimant followed to expose his "masks."
Scene II: Emilia and Busy tell Harriet they know of her composed song, making Harriet blush. As Dorimant arrives, Emilia tells him to mind his affairs with Harriet. He declares,
I will open my heart, and receive you where none yet did ever enter you have filled it with a secret.
Dorimant promises to renounce drink and all other women, but Harriet will not commit to marriage. In rushes Old Bellair, hoping to marry his son to Harriet--too late. Now the "masks" of deception are removed from many of the characters:
- Lady Woodvil learns Dorimant is not Courtage
- Loveit learns that the violence of her nature has ruined things
- Belinda is the "mask" with whom Dorimant deceived Loveit
- Dorimant reveals his love for Harriet and renounces all interest in other women.
Dorimant agrees to leave London and go to the country with Harriet although he still has some debt and affairs in London to clear up. The epiloque states, "Yet every man is safe from what he fear'd/For no one fool is hunted from the herd."