Episode 3 Part 3

Okay, so the previews for this episode looked so good, like I couldn't wait to see the whole thing!! But so far, for one guy, Iago is pretty convincing to Othello becasue they show Othello freaking out about the situation due to his jealous rage, so now, Iago believes it's the perfect time to fire him up even more. So they go to the beach and Iago starts to tell Othello that he heard Cassio mumbling about Desdemona in his sleep (which is the worst lie I've ever heard in my life) and that he didn't wish to speak of anything else he heard. But for some reason, Othello believes him, and he becomes so enraged that he basically turns to the dark side and makes a blood pact with Iago to kill Cassio and Desdemona for their betrayal. Are you kidding me?? Is he THAT stupid?