He makes it appear as though Cassio and Desdemona are involved together, having an affair. Othello does not believe Iago. "I do not think but Desdemona's honest. (Act 3, Scene 3, Line 228). He tells Iago that he is not a jealous man. Othello confidently says that Desdemona is faithful to him and he will not doubt her without any proof. Nonetheless, a tiny seed of doubt has been sowed into Othello's head. Iago's plan is working. Othello is beginning to feel the effects of jealousy and tries to stop the jealous thoughts, which is evident in the following quote. "No, Iago, I"ll see before I doubt; when I doubt, prove; And on the proof, there is no more but this: Away at once with love or jealousy!" (Act 3, Scene 3, Line 192-194). Iago will continue to feed many lies of Desdemona's fidelity into Othello's head until it results in Othello's destruction along with many others. As Iago continues to inform Othello of Desdemona and Cassio's supposed meetings, Othello begins to believe Iago's stories and his jealous nature is shown. Iago's next plan of action involves the beloved handkerchief, which was presented to Desdemona as one of Othello's first gifts to her in their days of wooing. This is a key feature in Othello's changing perceptions of Desdemona. "I will in Cassio's lodging lose this napkin And let him find it. Trifles light as air Are to the jealous confirmations strong As proofs of holy writ. This may do something. The Moor already changes with my poison- (Act 3, Scene 3, Line 322-326). Here Iago tells of how wife Emilia has picked up the lost handkerchief and given it to Iago who has continually asked her to steal it from Desdemona. With this handkerchief, Iago sets up Cassio. Iago plans to place the handkerchief so that Cassio finds it and then tell Othello Desdemona has given the handkerchief to Cassio as a sign of her affection and love for him. Othello becomes enraged, overcome with grief and jealousy and vows revenge just as Iago had predicted.
