Sam can see he should have acted with a little more tact when faced with Dean's doubt. It's late and he let the surprise of it overtake him. He pushes those feelings aside for something more thought out. "Dean, that's not at all what I meant to say. What I meant to say is that it won't be easy, but if you're willing to make it work and communicate with Jo, you should absolutely go for it. Honestly, the two of you, I think you'd be good for each other."