she tried to kill sam ,but she couldnt ,I dont rember why she couldnt unless it was sams powers or the demon blood thing sorry im not really sure about that one!!
Lilith wasn't able to kill Sam because she didn't hold any power over him as he was Azazel's chosen one and Lucifer's promised vessel. That's also why she tried to seduce him and make a deal with him in season 4. Lilith knew she couldn't kill Sam, so she had to resort to a different strategy to get rid of him.
