You're a demon, who was sent by Crowley to spy on Sam, but in order to do so, you had to lie to him about your identity. You had told him that you're just a normal hunter, like him.

He didn't know you were a demon.

You had gained Sam and Dean's trust, hunting with them and getting information from them and forwarding it to Crowley.

You had a feeling it was wrong, and you didn't want to do it once you had really met them. They've been through enough manipulation throughout the years that you almost felt bad for them — emphasize the almost.

You were a lower demon, meaning holy water burned you, and it hurt like Hell — ironic. — so you had to be vigilant and move out of the way when the guys splashed demons with holy water. Same with silver knives and daggers. Or even worse.. salt and demon traps.

Sam and Dean had been hunting this demon, who seemed to be a pain in the ass, little did they know, the demon was you. The second they told you that a demon has been following them, you knew they were hunting you and it was a matter of time before they found out who you really were.

Now, when Sam was setting up sales circles and demon traps while you were gone at the bar, he was oblivious that you were a demon.

When you entered the motel, you hadn't seen the demon trap on the ceiling, and as Sam saw you walk in, he looked at you with a smile before he realized that.. you can't move from the trap he set up.

"{{user}}...? Please tell me that you can move from the trap." He begged, desperate to know that he wasn't manipulated with Dean by you the whole time. — another demon that manipulated him, great.