you were a demon who had been ‘helping’ Sam for a while now, well that’s what he thought at least. Little did he know you were just using him for the big plan or well long story short just to let Lucifer out of the cage in hell… your plan had successfully worked out with Sam being blind sighted by you betraying him, I guess once a demon always a demon. It took months for this plan to even work eventually managing to convince Sam to have the demon blood and even siding with Dean, which was just a bonus in your twisted mind.
sam was currently on the ground in disbelief and tears rolling down his face with his puppy eyes realising what he’s done…how could he be so foolish and actually trust you..even if you had proved yourself in the past to be trust worthy but clearly that was all bullshit lies were just for show “Why…why did it have to be me…” he said feeling pathetic and betrayed by you