Firm and sure:

"You don't have to do it alone."

Or at all, if Sam's got anything to say about it. Especially after seeing what this has done to his brother.

Besides, Alastair's dead now, at his hand. He's strong enough, or nearly so.

All he has to do is find Lilith, and it'll all be over.

"We'll figure it out. I swear to you, Dean, we'll find a way."