Cassio's relations with Bianca give the reader or viewer a very bad impression of his character. Bianca seems to love him, but he is only using her and he despises her because she allows him to do so. It is almost painful to watch the scenes in which he treats her so contemptuously, while at the same time he loses the reader/viewer's sympathy. He is actually sadistic. No one except Desdemona could care whether such a heartless man would regain Othello's trust. It is hard to understand how he could have risen so high in the first place. When Othello commits suicide, Cassio ends up being appointed governor of Cyrpus. This man seems to have nine lives, like a cat. Obviously he has important social connections in Venice who are protecting him. He comes across as a selfish, incompetent fop and an incorrigible womanizer. His womanizing and braggadocio make it easy for Iago to convince Othello that Cassio is carrying on an affair with Desdemona. No man should trust Cassio with his wife. He seems perfectly capable of seducing Desdemona if he could get by with it.
Bianca is a Venetian prostitute who is in love with Cassio. However, Cassio does not share the same feelings for Bianca as she does for him. Bianca accuses Cassio of sleeping with another woman when he asks her to copy the embroidery pattern on Desdemona's handkerchief in Act Three, Scene Four. Cassio candidly tells Bianca to leave him alone after he gives her the handkerchief. In Act Four, Scene One, Iago tells Cassio that there is a rumor that he is going to marry Bianca. Cassio feels insulted and ridicules Bianca for being a whore. Cassio even mentions that Bianca follows him throughout Venice, and tells Iago that he has to get rid of her. When Bianca enters the scene, Cassio asks her why she is always following him. Bianca again insists that Cassio has been sleeping with another woman. Bianca is upset as she leaves the scene, and Cassio goes after her. Throughout their confrontation, Cassio is depicted as a selfish, insincere, chauvinistic individual. He continually plays mind games with Bianca by telling her that he loves her, but continues to treat her terribly.