Yes, she is. I know you won't believe that she could possibly be anything other than a monster. I didn't believe it for a very long time. I was raised to fight demons, to keep them away from innocent people, and seeing Sam marry her went against almost everything I believed in. Ruby is family now, though, and I know she would never willingly hurt Sam.
No, that was just when he was drunk, he wouldn't ...oh He loves his wife. You've already made another choice though. You didn't take the deal she did, and so you've already changed things where you're from. No one should make you be evil.
Do you know how to keep a demon out of your home? The words to make them reveal themselves?