Mrs. Fainall enters the dressing room. Seeing Foible distressed, she tries to comfort her and find out what has happened. Foible tells her that she and her husband are doomed to be sent to prison. Mrs. Fainall informs her that Mirabell has gone to post bond for Waitwell’s release. She recognizes Marwood and Fainall’s hand in this turn of events. Foible tells Mrs. Fainall how Marwood came by the information by hiding in the closet, sent an anonymous letter, and then how Fainall had Waitwell arrested while he went to go get the deeds and engagement document, and Marwood approached Wishfort and told her everything.
Foible and Waitwell suffer a harsh reversal of fortune. From being happily married in the morning, now they face the possibility of spending years apart in prison. The repercussion of participating in Mirabell’s scheme now greatly outweigh the rewards he promised, as they realize the cost of being associated with Mirabell (especially as poor people; Mirabell certainly isn’t going to prison). The one good thing is that Mirabell does not desert his supporters and provides them a different type of financial help, one that secures their freedom from jail, at least.
Mrs. Fainall realizes that, if her mother knows everything, then she also knows of her own affair with Mirabell. She tells Foible that her comfort is knowing that today is the last day she will have to live with her husband. Foible wants to give Mrs. Fainall more comfort and so informs her of her husband’s affair with Marwood, which she knew nothing about. Mrs. Fainall is excited and asks Foible if she can prove that they are having an affair.
Mrs. Fainall, though her reputation is in jeopardy, is excited by the prospect that she can finally come clean about her bad marriage and perhaps, leave Fainall. The prospect of escaping the deceit of her life outweighs her fear of shame. And she still has the wit to recognize the possibilities ingredients for a counter-plot.
Foible says that she can prove it. She tells her that Mincing also knows about the affair, too, but that they were bound to secrecy by Marwood, who made them swear not to tell. However, Foible says that she has no qualms about breaking the oath because they made the oath by swearing on a book of poetry, not the Bible.
Foible easily finds a loophole in Marwood’s pact, not only because she’s clever, but also because her loyalties lie with Mirabell and not with Fainall. As Mincing’s loyalty lies with Millamant, getting her to reveal what she knows won’t be hard for Foible to do.