The lesson I Learned from a Fake friend

Currently, I am in a pharma college, pursuing my master's degree. This is the same college where I completed my bachelor's too. During my master's, I met a person who was completely new to me. At first, I was not very sure about the person, as she was new and seemed a little bit weird and arrogant. I don't talk much to people, as I am an introvert with people whom I don't know. But after some time, I started opening up with my classmates. Everyone was good except her; she was jealous of me, and she used to behave strangely in front of teachers to make me look bad, so I didn't like her. In my master's, we often had presentations, and whenever it was my turn, she would ask weird and unnecessary questions. One day, I confronted her about it, but she denied everything and said that she had never done anything like that. After that day, I slowly started trusting her again. But one day, after our guide distribution in the 2nd year, she was angry with us because she got the guide she didn't want, and I and my friend got the guide she wanted, so she was sad and jealous. The teacher she got was not nice to me; he and I had a tiff, and I completely did not want him because he wanted to take revenge on me, so before guide distribution I cried a lot and said some things about the teacher that were not nice, as I don't like him and also he was not a good person. At that time she was silently listening to me, but the moment she got that teacher, she behaved differently, maybe because she didn't get the teacher she wanted and I got him; she was completely jealous of me and my friend. So she went to the teacher to greet him, as he was her guide; there she started uttering bad things about me in front of him. She told everything that I said about him, forgetting that I was her friend. The teacher too said bad things about me after that to one of my very close friends, who was a close friend of that teacher too. When I came to know about that, I felt very bad and helpless, as I trusted a fake person again. He commented on my character and also said that he will take revenge during the synopsis as she added things from her side too that were fake. I felt more helpless due to this because she lied a lot, but I was unable to do anything. That day I decided to not trust anyone like this because anyone can turn into an enemy when you get something better than them and start spreading fake rumors about you. I learned that friendship nowadays is a rare thing, and not everyone can know the genuine meaning of friendship these days, so it's better to be alone than to have fake friends.