Marwood returns to the living room, with Fainall following. Fainall addresses Wishfort and tells her that the time for her to deliberate has run out. He produces an “instrument,” a contract for her to sign that gives him power over her fortune.
Finally holding the “instrument” of Wishfort’s undoing in his hands, Fainall thinks that he is going to be victorious against Mirabell and Mrs. Fainall.
Wishfort replies that even if she were ready to sign, she no longer needs to because Millamant has agreed to marry Wilfull, a move that legally prevents her from turning all her fortune over to Fainall. At first, Fainall doesn’t believe this could be true. But Millamant assures him that she is prepared to marry Wilfull and Mirabell confirms that he has broken off the engagement, leaving nothing in the way of the marriage.
Fainall’s plan isn’t exactly bulletproof. He did not foresee the possibility that Millamant would actually agree to marry Wilfull. He should be more suspicious that Mirabell is giving up so easily. However, his greed and the proximity of success blinds him to the fact that his adversaries are a lot more cunning than he gives them credit for.
Wilfull, too, speaks out against Fainall, threatening to use his “instrument,” meaning his sword, to slice through Fainall’s contract if he does not revoke his demand. Wishfort and Millamant both tell Wilfull to calm down. Fainall tells Wishfort that it doesn’t matter if Millamant has found a way to save the £6000 dowry because he is still going to have Wishfort’s share of the fortune, as well as his wife’s portion. Otherwise, he threatens that he will turn his wife out and tell the town about her affair with Mirabell.
Wilfull reveals his confidence through deeds of strength and bravery rather than in a clever come back. This is not appreciated by the women of the group, who prefer when men use language to do their fighting rather than immediately suggest the use of actual weapons. Fainall again reveals his willingness to shame a women in exchange for gaining her fortune.
Wishfort wails for a way to prevent Fainall from ruining her. Mirabell begins to answer that he knows of a remedy but dismisses his idea because he is sure that she will not accept help from him.
Mirabell has been waiting for Wishfort to say this, carefully calibrating the moment for him to offer his help. And he says it diffidently to ensure that Wishfort draws it out of him rather than feeling like he is pushing it on her. He’s a real master.
Hearing this, Wishfort grows excited and hopeful. She tells Mirabell that she will forgive him for everything he’s done if he prevents Fainall’s plan from succeeding. Mirabell agrees to help her even as he laments the loss of the one reward that he desired, Millamant’s hand in marriage. Wishfort praises him for being so generous and promises to give him her niece and her fortune, if he saves her from ruin. Mirabell accepts her offer and then asks if she will allow two criminals to come forward. Wishfort readily agrees and Mirabell calls Foible and Mincing into the room.
Mirabell has successfully manipulated Wishfort into not only giving him what he wanted in the first place but gets her to praise him while giving in to him. Now in complete control of the situation, Mirabell slowly begins to reveal his trump cards to the entire group.