It means that she is not in the mood to discuss whatever topic it is you are talking about. The smartest thing to do would be to just let her have some space and don't bug her about it.
If mean she/he wants you as a girlfriend/boyfriend
That he likes you and want you to be his girlfriend.
lots of love
It means your in buddy
she wants to be with you forever/ your relationship is forever
It means that he likes you a lot and would probably date you if he did not have a girlfriend.
It means she's not your girlfriend any more.
It means he will talk to you later. Guys say exactly what they mean.
he probably means that he likes you as a friend, but doesn't as a girlfriend
She's breaking up with you.
She is two timing you.
that probally means he can be your BFF or you girlfriend