Thats how the Slayer had put it and it wasn't far off, not that Ruby felt she had to proove herself to Sam anymore but she was still a demon. Still his family, his friends would have issue with her and she did understand it in many ways. Even Castiel had his reasons for despising her. But luckily most were willing to trust Sam at his word.
But Azazel had gotten to her much as she didn't want to let herself believe his words. Sam had said he'd need reason to send her back to the pit. But Azazel as usual had managed to twist things just enough to put that doubt in her mind.
Dean, John Winchester, the mother...both of her, that had recently arrived. Their girlfriends, friends. The Slayer she was about to meet. She hadn't entirely been kidding when she'd compared her to the brothers. They had the same kind of outlook on things. Though Faith, from this world had a broader view of demons.
She waited, a street away from Bela Talbots home for the Slayer to arrive ready to prove herself. Ready to get the colt for the Winchesters. And like her knife it could kill her.
But she knew well that they needed rid of the yellow eyed bastard all over again. And it would take a Winchester to do it. With the gun that Talbot had hidden away.