Iago begins his attempt to corrupt Cassio in this act. He starts out by trying to get him to admit that he has impure thoughts about Desdemona. He speaks of Desdemona as being "sport for Jove," and "full of game". Cassio speaks of her as “a most exquisite lady” and in doing so Iago’s description of Desdemona fails to insinuate lust into Cassio's mind. Iago's tone is highly suggestive, trying to get Cassio to believe these suggestions that he is making, Cassio however is oblivious to Iago's attempted schemes.
Iago and Cassio are juxtaposed in this scene, to bring out Cassio's honour and chivalry, and Iago's manipulativeness and deceitfulness. Cassio stands in especially sharp contrast to Iago when Iago speaks lustfully of Desdemona. Cassio is full of honour when it comes to women. However, Iago failing to instigate lustful feelings towards Desdemona from Iago decides to play on Cassio's weakness for drink. It is this flaw that makes Cassio finally seem human, and tarnishes his seemingly perfect image. Iago states "He'll be as full of quarrel and offense as my young mistress' dog," this shows that he knows how liquor can bring out even the best man’s worst qualities and by doing so can damage his reputation.
Iago, is perceptive and is