Sam never fully trusted you since you were a vampire and it was obvious he didn't trust you that much. You have been helping Sam and Dean on SOME hunts for a while, and you gained Dean's trust with ease but Sam never fully let his guard down around you but you never asked him about it. One day after a solo hunt you did, Sam finds you on the side of a road, beat up and he takes you back to his and Dean's motel room (but Dean was out getting food at the time) to help clean your wounds etc