Iago could commit nearly any possible action after this statement and it would still seem believable to the audience, as they recognise him as slightly un-hinged. Right from the beginning, Shakespeare has created vigorous dialogue and conflicting situations.
Shakespeare does not allow Othello to kill Iago as proof. His motives are entirely self-orientated, it is clear that Iago does not have any compassion for any character, not even his own wife who he murders in the final scene as a last attempt to avoid discovery.
Just as Othello seeks revenge on his own wife for the same reason, and yet Othello is entitled as the tragic hero. Even though he is often referred to as "Honest" Iago, he lies, cheats, steals, bullies, and even kills just to get what he wants Iago as 1.
The primary and predominant cause that brings about the tragic downfall of Othello is Iago's highly sophisticated art of dissembling, and his unbelievable understanding and ability for manipulating the mind and feelings of the every other character.
He is quick witted and that is what makes him a successful villain. Although Iago serves Othello and appears to be companions with him he claims that he truly despises him because he was not chosen as his lieutenant.
Iago uses Emilia as part of his plot.
After all the lines dedicated to describing how fair and just Othello is, it is highly unlikely that Shakespeare wrote this line as truth. In Act 2, Desdemona is awaiting the return of Othello from the courts. Shakespearean audiences demanded morals and values to be displayed and therefore a punishment had to be undertaken by the playwright.