You haven't seen anything? Have you seen her and cassio together?
No,and i didn't suspect anything at all. Yes, but i didn't see anything wrong.
I do hate him, I Swear.I will ruin his life.
If you don't like him you should quit.
Iago is starting to give othello some evidence that desdemona is cheating on him with cassio and he have the handkerchief. Iago is making othello to be on his side and to to trust him in everything that he says.
Othello is asking emilia in a nervous and threaten her if she have seen or heard anything between desdemona and cassio.
Iago knows that othello married desdemona in secret, he knows that roderigo loves desdemona. he is convincing roderigo to go and tell brabantio that his daughter is married in secret without his knowledge. Iago is telling roderigo that he would talk to barbantio because iago can't be appeared in the photo because othello will know that he hates him.