Othello

"She deceive her father by marrying you; and when she seemed to shake and fear your looks, she loved them" (3.3.206-208)

This is the very moment Iago triggered Othello's insecurity himself. Start to question the friendship between Cassio and Desdemona. What makes Othello more vulnerable was the fact that Iago implied his color was part of the problem. Also let not forget his response to Desdemona's "my life upon her faith," he is basically saying he swear on his life she will faithful.

ruminate: to think carefully and at length about something

exsufflicate: frivolous