They think you have potential. If they are not very good with giving compliments, or really don't like giving them, they are likely to use such a phrase. They may also want to avoid giving you any sort of complex about being really good, as that sort of attitude is contrary to good training.
The person who told you that was criticizing you.It means that youre not that intelligent.
That youre a fake
In the ghetto terms ; trick means slut, hoe, skank, etc .
That could mean to contradict the other person or undermine what they are saying.
It means that youre really becoming part of someone's life. something like that..like, it means, youre really becoming something important to that someone.
Sorry, but you guys won't last
Your signature.
When someone tells you to be mature it means to( "act your age").
Fight them
A snitch is someone who tells or tattles on someone else's wrongdoings. It's an insult.
It means that that you are seriously ill.
It means that you are less than what they are looking for.