Incorrect conclusion

A couple months ago I met someone who seemed to be an extraordinary person. Her grades were great, she was very kind to everyone, many people were very fond of her, and she appeared to be the sweetest and most harmless person in the world. She never did anything wrong and I was very fooled by what she appeared to be. Unfortunately, I discovered a side of her that I would have never thought she had. I went over to her house to work on an assignment for class. She had previously told me to invite myself in when I arrived because she was going to be taking a shower and she wasn’t going to be able to open the door. Because of this, I tried coming 30 minutes earlier so that she would know I was there, but when I arrived she never opened the door. I invited myself in like she told me to do as originally planned. As I headed towards her room, I could hear her loudly speaking over the phone about how tired she was about faking the friendship she had made with my friends and I. What was worst was not that she was faking every single part of herself, but that she was doing it so that she could steel my friend’s boyfriend. She apparently was after him for a very long time. As she spoke to her mother, it seemed like her mother encouraged this behavior until it was possible for the girl to get what she wanted. I was shocked. I would have never thought this from someone in our circle of friends, especially her. This actually got me thinking that narcissist disorders actually exist. This behavior shows many attributes of this disorder and a couple other scientific finding on personality disorders as well.