She tells all assembled that Iago begged her to steal Desdemona's handkerchief for him, and she reveals that he has intentionally framed Desdemona and manipulated Othello. For this, Iago stabs her with his sword, killing her.

How Desdemona was killed?

When her husband is deployed to Cyprus in the service of the Republic of Venice, Desdemona accompanies him. There, her husband is manipulated by his ensign Iago into believing she is an adulteress, and, in the last act, she is murdered by her estranged spouse.

What happened to Desdemona?

Iago manipulates Othello into believing his wife Desdemona is unfaithful, stirring Othello's jealousy. Othello allows jealousy to consume him, murders Desdemona, and then kills himself.