I never knew
A Florentine more kind and honest.

– William Shakespeare

Othello, Act 3, Scene 1. Cassio’s statement that Iago is one of Florence’s most honest men is a very clear example of dramatic irony. It also highlights Cassio’s blindness to Iago’s Machiavellian ways. Far from being honest, Iago has been manipulating Cassio and is the one who got him dismissed as Othello’s lieutenant.