Jason/Castiel
Did he know that his wife would be murdered, his child turned into a monster-hunter, and he himself be killed in the service of the Lord, while I continue to wear his vessel around long after? No.
But he did know there were risks. He did know it would be unpleasant. I warned him it could hurt and that his faith would be tested.
He left his wife and child, who believed him to be insane, so that he could host me. He made an informed choice, based on the information available at the time.