I know, Iago,
Thy honesty and love doth mince this matter,
Making it light to Cassio. Cassio, I love thee
But never more be officer of mine.

– William Shakespeare

Othello, Act 2, Scene 3. We see an example of dramatic irony when Othello praises Iago’s honesty and love. This is after Iago explains Cassio’s part in a drunken brawl. Othello is completely taken in by Iago’s claim that he doesn’t wish to get Cassio in trouble. But the audience knows the truth: Iago was the one who planned the entire situation in order to get Cassio in trouble and discredit him in the eyes of Othello. A rash Othello rushes to judgment and immediately dismisses Cassio as his lieutenant. This character flaw of Othello, who is too quick to believe one side of a story without fully investigating it for himself, will later lead to his downfall.