o's real problem is that he wants to set things right with Othello. He is deeply hurt and ashamed that Othello has removed him from his post, and he believes that he can find a way into Othello's good graces once more. This makes him susceptible to Iago. Iago uses the young man's desire to ingratiate himself with Othello to nurture Cassio's friendship with Desdemona, and in this way he can deceive Othello that there is more to this relationship than friendship. Cassio is ultimately successful and is given control of Cyprus as a reward for his virtue, but his virtue itself makes him susceptible because like Othello, he tends to believe others are as sincere as he is himself. Iago is always a good judge of character and knows precisely which aspects of a person's character to use to his own ends, and he makes good use of Cassio's trust and virtue while twisting both into a semblance of their opposites.
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