Be thou assured, good Cassio, I will do All my abilities in thy behalf.
Bounteous madam, Whatever shall become of Michael Cassio,He’s never anything but your true servant.
Cassio, my lord? No, sure, I cannot think it That he would steal away so guilty-like Seeing you coming.
Was not that Cassio parted from my wife?
What handkerchief? Why, that the Moor first gave to Desdemona, That which so often you did bid me steal.
No, but she let it drop by negligence And, to th' advantage, I being here, took ’t up. Look, here it is
Hast stolen it from her?
Desdemona and Cassio have a conversation about Desdemona talking to Othello in order to get Cassio his position back.
I will in Cassio’s lodging lose this napkin And let him find it. Trifles light as air Are to the jealous confirmations strong As proofs of holy writ. This may do somethingThe Moor already changes with my poison.
Iago plants idea in Othello's head about Desdemona possibly cheating on him, after she is seen walking away from a chat with Cassio. Othello is not very happy.
'Tis a shrewd doubt, though it be but a dream. And this may help to thicken other proofs That do demonstrate thinly
But this denoted a foregone conclusion.
Emilia finds the handkerchief that Othello gifted to Desdemona, and she gives it to Iago because h wants it for his scheme.
I have a salt and sorry rheum offends me. Lend me thy handkerchief.
I have it not about me.
Iago plants the handkerchief in Caasio's lodgings as part of his scheme against Othello because he knows that Othello already has suspicions about Cassio and Desdemona, and Othello finding the handkerchief will only confirm his suspicions.
Othellos begs Iago to tell him about proof of Desdmonas cheating. Iago tells Othello that he heard Cassio yell out Desemonas name while he was sleeping and he also said that he saw Cassio wipe his mouth with the handkerchief that Othello gave Desdemona.
Desdemona doesn't have the handkerchief that Othello gave him and Othello gets suspicious