Iago, while pretending to reassure Othello, is rubbing salt into his wounds. Their conversation is of hypothetical acts, whether they constitute betrayal or not, but Othello imagines them all being acted out by Desdemona and Cassio. But this is just the warm-up to the topic that Iago has discovered can most easily rouse Othello's passions: the handkerchief. Othello, in his thinking, assumes it is a symbol for his wife's honor, but Iago plays at thinking it is only a handkerchief: "being hers, she may, I think, bestow't on any man" (13). He repeats again the word "handkerchief," and Othello cries out.
Iago can see that Othello is at the edge of madness, and there is no way he can judge just how far to push him, considering his unexpectedly violent previous reaction. However, Iago cannot afford to leave Othello in his present frame of mind, where he might do something unpredictable. Therefore, he proceeds to tell Othello the direct lie: that Cassio has confessed to a sexual affair with Desdemona. Iago uses again the successful technique of hesitation, forcing Othello himself to say what Iago would have him think. Iago, the liar, comes back to the word "lie" when telling his untruth so that the word "lie" echoes with double meaning through their conversation, lacerating Othello with thoughts of two illicit lovers and, at the same time, accusing Iago for his abuse of the truth.
Othello is now raving; his words come in an anxious jumble around "handkerchief," and "confess" until he falls down in a faint. The overstressed mind seeks refuge in unconsciousness. Instead of pity or alarm, Iago only expresses satisfaction that his medicine (poison words) is working.
