Well Mr. Ryan Junior, that's not an answer that's going to satisfy Sinclair.

"If any of this is gonna work," he says with a vague gesture, "you're going to have to come clean at some point. If there's anything I need to know about you or your circumstances, son, you've got to tell me. I need to be able to trust you."

Okay, so it's something of an empty emotional appeal. He doesn't need to trust Jack with anything just yet, but to fair he may very well need to some time in the near future. You never know.