attempts to kill Iago. Later on, Cassio tells Othello that Iago admitted to placing the handkerchief in his room, which confirms that Othello has been tricked. Before Othello commits suicide, he tells Lodovico to describe him exactly how he is. Othello takes responsibility for his actions and accurately describes himself by saying,

Then must you speak Of one that loved not wisely, but too well. Of one not easily jealous, but being wrought, Perplexed in the extreme. Of one whose hand, Like the base Indian, threw a pearl away Richer than all his tribe (Shakespeare 5.2.360-365).

Overall, it is Emilia who reveals the truth to Othello by explaining how Iago manipulated him by using Desdemona's handkerchief. Iago's response also indicates that his wife was telling the truth, and Othello immediately recognizes his fatal mistake.

Arguably, the moment of truth, or the epiphany, for Roderigo comes in Act V scene 1, when he is stabbed by Iago and he dies realising suddenly just how stupid and foolish he has been and how easily he has been used by Iago for his own purposes. Of course, at various stages in the play Iago has had to do some very fast talking with Roderigo to persuade him not to give up in his love for Desdemona, and he only manages to do this by telling him that her attraction to Othello is based on a lust that will pass. However, it is when Roderigo is stabbed by Iago that he realises just how he has been duped. Note what he says to Iago at this stage:

O damned Iago! O inhuman dog!

Clearly, this represents Roderigo's moment of truth where he is forced to see the reality of his relationship with Iago and, by consequence, just how much he has been manipulated by him, resulting in his death.

Throughout the play, Desdemona is defined by her loyalty and love for her husband, Othello. When Emilia tells her that she should be wary of all men, as they are all inclined to commit adultery and otherwise abuse their wives, Desdemona will not hear it, telling Emilia that she is cynical to think so. She is sure that her husband would never betray her and that he would never think ill of her.

It is in act V, scene II that this changes. When Othello awakes Desdemona with his soliloquizing on the murder he intends to commit, Desdemona still suspects nothing. She asks him to come to bed. As Othello continues to speak, however, she becomes aware that his words are strange. Her suspicions are aroused when he suggests that she should "solicit" heaven for any crime she has not prayed forgiveness for; she asks what he means by this request. Othello tells her, "I would not kill thy soul."

It is in this moment that Desdemona recognizes the situation she is truly in. She asks heaven to "have mercy upon me." Still, however, she is not sure that Othello will go through with this threat, saying she hopes he will not kill her but admitting that she feels "fear" of her husband for the first time. She is viewing Othello now in a new light.

When Othello begins to explain to her why he intends to kill her, Desdemona seems to enter a state of panic. She begins to bargain with Othello, asking him to have mercy on her and stating that she "never did offend you in my life." At this juncture, she thinks there is still a possibility of her convincing Othello that all has been a misunderstanding. It is only when she hears that Cassio's "mouth is stopp'd," as Othello believes, that she seems to realize that she is "undone." At this point, she falls upon emotional entreaties, begging Othello to delay her death until the following night, but it is too late—at this point, Desdemona knows that Othello, whom she loved so much, is really going to kill her, and there is nothing she can say to stop it.

Emilia experiences her moment of truth in the last act of Othello shortly after Othello has murdered his wife. Othello tells Gratiano

'Tis pitiful; but yet Iago knows
That she with Cassio hath the act of shame
A thousand times committed. Cassio confessed it,
And she did gratify his amorous works
With that recognizance and pledge of love
Which I first gave her. I saw it in his hand.
It was a handkerchief, an antique token
My father gave my mother.

EMILIA
O God! O heavenly God!  (V.2)

At this exact moment Emilia realizes why her husband wanted her to give him Desdemona's handkerchief. She plays a pivotal role in Act 5, Scene 2, because she not only knows the whole truth about Iago's villany but she is so devoted to Desdemona that she insists on revealing Iago's treachery to Othello, Gratiano and Montano before she is stabbed by her husband. His act of stabbing her demonstrates his vicious character and serves as tangible proof that she is telling the truth about his machinations. Emilia also realizes in her moment of truth that she is largely responsible for the death of her mistress and that she is married to a most sinister villain.

For Iago, the moment of truth comes very late in the play, when Emilia reveals his duplicity involving the handkerchief that Othello gave Desdemona:

O thou dull Moor! That handkerchief thou speak'st of 
I found by fortune and did give my husband; 
For often with a solemn earnestness, 
More than indeed belong'd to such a trifle,
He begg'd of me to steal it.

Othello realizes, to his horror, that he has been duped into murdering his innocent wife. At this point, Iago's trickery is revealed, and the seeming spell he has over Othello is broken. Othello charges at him with his sword, and Iago kills his wife. As Lodovico and Gratiano arrive to discover what has transpired, Iago swears he will not reveal anything about his plot, saying:

Demand me nothing; what you know: you know. 
From this time forth I never will speak word.

Gratiano replies ominously that torture will cause him to speak. So it is at this point that Iago finally experiences his moment of truth, even if the audience is denied the pleasure, and the sense of justice, of hearing a full confession or witnessing Iago's death.