Disappointment with someone

I felt really disappointment with someone, and I really don't believe she is that kind of person. How can someone who is very good and nice to you and turn up to be another person.

This is what my aunt say that when working outside....won't have any real friend....and just can be colleague and can't fully trust each other. At first I don't believe what my aunt said.....but now I somehow believe it this word. Because something shocking make me don't trust her......but I won't say out here....sorry.=(

I hope this person is not what I think now.......right now I can't find of any solution to solve this problem....but one day I may talk to her about it and find out the problem. Hope that god will give me some clue and solve this problem........pray hard!!!!!!!!!!!!!!!!!!!!!!!!!!!!!