In conjunction with nobility, the tragic hero possesses a flaw which leads to his demise. Early in Act 3, Iago sows the seeds of jealousy in Othello when he says how he can't conceive why Cassio would "steal away so guilty-like" (3.3.40-41). Othello, in some ways, already feels inferior to Cassio. Othello doubts Desdemona's love because he is black, much older, and less handsome than Cassio. He is also very well-known, therefore, subject to many passing loves. At one point, Othello gives Desdemona a handkerchief with embroidered strawberries on it as one of his first gifts to her. This simple family heirloom is of great importance to Othello. He believes that as long as Desdemona keeps the handkerchief, their love will flourish. But if she loses it or gives it away, their love will perish eternally. Later on, Cassio will have the handkerchief in his possession and it will be "proof" of Desdemona's infidelity. As the play progresses, Iago creates more jealously in Othello. He makes it so that Othello "can't eat or sleep" (3.3.433). Iago makes up a dream in which he says Cassio kisses him and puts his leg on Iago's thigh and curses fate, which "gave [Desdemona] to the Moor!" (3.3.421-426). Othello's outrageous jealousy is observed when he claims, "I'll tear her, all to pieces!" (3.3.433). The pivotal point of Othello's jealousy occurs when he makes up his mind to believe Desdemona is unfaithful (3.3.460-463). There isn't any question in his mind, he's positive of his decision to kill Desdemona. Othello's character has now succumbed to a complete change.
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