Iago has made assumptions about moor’s an women in act II in order to trick the people around him so they can turn on each other. Iago says in line 120 “Nay, it is true, or else I am a Turk.
You rise to play and go to bed to work.” By this he means that women are evil and have all the fun they can get in the daytime and are lazy to do anything but wait till nighttime and make love to their husbands which is their work according to him. This saying by Iago makes the women go against him and the key man Cassio to go against him too which was his goal. He wanted Cassio to look like the gentleman in the situation so that he can frame him for being close to the moor’s wife in a sexual way. Later on Iago tells Roderigo that Cassio is going to have a sexual relationship with Desdemona and explains that a woman like her wouldn’t stay with a moor because he looks ugly, is old, and un-interesting. Then he gets Roderigo to start a fight with Cassio since he wants to take Cassio out of the picture since he got tricked that Desdemona and Cassio love eachother. This is the way that Iago pulled of his plan and he is a very sneaky man and doesnt care about anyone else but himself and getting that position he thinks he deserves.