Iago constantly tells other characters slight untruths or outright lies. His constant use of lying puts the audience on edge because they always know when he has lied. One of his major lies is when he tells Othello that his wife, Desdemona, is having an affair. His proof of this is a handkerchief of Desdemona’s he “found in another man’s room”. He tells Othello “I know not that; but such a handkerchief-- / I am sure it was your wife's--did I to-day / See Cassio wipe his beard with” (Act 3 Scene 3 Ln 438-440). Because the audience knows that Iago planted the handkerchief they are anxious to see how Othello will react to this lie. In a similar vein, Iago tells Othello about Desdemona’s “affair” and then states that “[He] hope[s] [Othello] will consider what is spoke / Comes from [his] love” (Act 3 Scene 3 Ln 217-218). The audience know that this is completely ridiculous, because Desdemona is not having an affair and because Iago hates Othello. Both of these are examples of Iago telling outright lies and the audience waiting in suspense to see if Othello will fall for them.
Dramatic irony can also be seen when Iago misrepresents his personality to other characters. For instance Iago tells Othello, “My lord, you know I love you” (Act 3 Scene 3 Ln 118). However the audience knows that this is completely untrue; Iago hates Othello with his “free and open nature” (Act 1, Scene 3, ln 12). They are then left in complete suspense as to what Othello’s reaction to this lie will be and how it will affect the rest of the play. Another example of this would be when Iago says, “O, beware, my lord, of jealousy; / It is the green-eyed monster which doth mock / The meat it feeds on; that cuckold lives in bliss /