"I will wear my heart upon my sleeve for daws to peck at; I am not what I am." (Act I, Scene I, lines 64-65)
What does it mean? In this opening scene, we see Roderigo and Iago talking about Desdemona and Othello. The ever cunning Iago is revealing an important fact about himself; he will manipulate and act deceptively if it suits his motives. The audience should understand that Iago is not to be trusted. This scene also shows how naive Roderigo can be. Roderigo doesn't take Iago's words to heart. Roderigo dies later in the play because of Iago.
"To mourn a mischief that is past and gone is the next way to draw new mischief on." (Act I, Scene III, lines 204-205)
What does it mean? The Duke is talking to Brabantio, Desdemona, and Othello. The Duke is trying to smooth things out between Brabantio and the young couple after Brabantio publically disowned Desdemona. The Duke is saying that it's useless to hold onto a grudge, and if something happened in the past, then leave it in the past and move on.
"T'is neither here nor there." (Act IV, Scene III, line 58)
What does it mean? In this short, but pivotal, scene Emilia and Desdemona discuss marriage, husbands, and fidelity. After her Willow Song, Desdemona asks if Emilia minds Desdemona's crying. Emilia's response means that it doesn't matter to her.
"[w]ho would not make her husband a cuckold to make him a monarch?" (Act IV, Scene III, lines 74-75)
What does it mean? Emilia and Desdemona are discussing marriage in this scene. Emilia is really saying that she would cheat on her husband if they had something to gain from it. Desdemona can't understand this reasoning; she's forever devoted to her husband. This exchange highlights the differences in moral codes between the two women. Throughout the play, Desdemona is presented as virtuous and innocent. The scene adds to the image of Desdemona being innocent and makes her death even more tragic.
"I kissed thee ere I killed thee, no way but this, Killing myself, to die upon a kiss." (Act V, Scene II, lines 359-360)
What does it mean? In his last words, Othello speaks to his murdered wife. Because he kissed her before he smothered her, he kisses her once more before he takes his own life. Othello is speaking poetically about his relationship with Desdemona. His love, and eventual jealousy, killed Desdemona. If he had never loved or kissed her, she never would have died. So, Othello kisses her again and kills himself, as his personal repentance.