Othello's characters believe him to have only the best of intentions, even going as far as to call him "honest Iago," completely unaware that he spends every unwatched second plotting their undoing.

Iago is a Machiavellian schemer and manipulator, as he is often referred to as "honest Iago", displaying his skill at deceiving other characters so that not only do they not suspect him, but they count on him as the person most likely to be truthful.

Everyone calls him honest Iago.

O brave Iago, honest and just, That hast such noble sense of thy friend's wrong!

So, rather than portraying Iago as a "mustache-twirling villain," he shows how "honest Iago" had long been Othello's close friend and companion-in-arms, how Iago's whisperings about Desdemona's unfaithfulness would seem credible.

CASSIO: Good night, honest Iago.

OTHELLO 'Tis he:--O brave Iago, honest and just, That hast such noble sense of thy friend's wrong!

My friend, thy husband, honest, honest Iago.

He then asks "honest Iago" to explain how the duel began, but Iago says he doesn't know.