Can anyone provide proof of fidelity in Othello act three scene three?

Here is the requested proof of fidelity in Othello act three scene three.

Desdemona: Is he not jealous?

Othello: Who? he? I think the sun where he was born

Drew all such humours from him.

Othello is certain that Cassio is not jealous, demonstrating his faith in Cassio's trustworthiness and loyalty.