"I have not deserved this."
Desdemona says this to Othello who is treating her with contempt while in the presence of the Duke and Senators of Venice. Othello believes her to be cheating on him, which she is not. Thus she has no clue as to why he is acting in such a way toward her.
"There's magic in the web of it."
Othello tells Desdemona that the handkerchief he gave her is special from his mother and he wants to see it. This object matters greatly, as Iago has set Othello up to make him believe that Desdemona has given it to Cassio in order to overthrow Othello.
"Soft you a word or two before you go."
Othello is about to be taken away after murdering Desdemona. However, he demands to be given the opportunity to speak after he's found out that Iago has set him up to kill his own wife.
"If I be left behind a moth of peace"
Desdemona tells the Duke and her father Brabatio that she wishes to follow Othello. She does so in a very controlling manner. The iambic pentameter in the quote shows this as she says it with a soft yet strong beat. If I -- be left -- behind -- a moth -- of peace. She uses a creature such as the 'moth' to demonstrate to her father how lost and vulnerable she will be without her 'light being Othello.
