OTHELLO: Think on thy sins.
DESDEMONA: They are loves I bear to you.
OTHELLO: Ay, and for that thou diest.
– William Shakespeare
Othello, Act 5, Scene 2. When Othello demands that Desdemona think of her sins, she answers that her sin is her unconditional love of him for which she went against her father. But to Othello her sin is having betrayed him and for that she must die.