"My brother is trying to kill me and is extremely sneaky and manipulative so I believe everything he tells me and allow him to isolate me from everyone else in my life." - The MC
Plus IT WAS A CONTRACT RELATIONSHIP. He knows they were both getting something out of it and the ML wasn't with him for love. Acting like this is some sort of surprise is stupid, it's like the author forgot their own story.
"My brother is trying to kill me and is extremely sneaky and manipulative so I believe everything he tells me and allow him to isolate me from everyone else in my life." - The MC