Iago tricks Cassio into speaking about Bianca, a woman he is having an affair with, while leading Othello to believe Cassio is describing Desdemona. As a result, Cassio’s comments, such as “She is persuaded I will marry her / Out of her own love and flattery, not out of my promise” (4.1.) sound to Othello like Cassio is admitting to sleeping with Desdemona. The confusion between Desdemona and Bianca is significant because Bianca’s status as a prostitute means Cassio does not respect her. Iago points out that “He, when he hears of her, cannot restrain / From the excess of laughter” (4.1.). Othello is enraged because he believes he is hearing his wife being joked about and described like a prostitute, but he also can’t help seeing her in that light. Othello goes on to refer to Desdemona as a whore a number of times, presumably because of the way he believes she has been treated by other men.