How would you describe someone like this

How would you describe someone who acts loving to someone that he/she would never actually date and is not interested at all in that person, but continues to act loving and in a way that might or does show the other person that he/she is interested in them, but their really not. And than makes the other person fall for them? has anyone here experianced this?

I'm not in this situation and never have been and never will be but i do see it happening with other people, thanks :)

There are many different answers for this. We're going to need specifics.

My immediate reaction is a flirt, but as Matthias stated, it's not specific enough to go much beyond that.

~Sphinx