Tell her the truth, for her own good she needs to hear it. But prior to that I believe knowing the truth about this boy is wise. Otherwise you end up the fool.
Explanation:
You want to be the best friend you can be and that doesn't always mean your friend will like you for it, at least not at first. But at the same time, you need to make sure you've done your homework on the guy your friend likes because you don't want to give into rumors. It is always wisest to get your facts straight before you tell your friend about her crush being a bad guy.
