Notes

There is this girl, she is not normal, I cant understand her but one thing i can understand that she makes me feel bad and uncomfortable most of the time.
she compliment me but in same time she says hurtful things all the time including insults. She doesn't know any boundaries.
If i had a call and i walked away to talk privately, she would follow me and listen to me talking, she would open my bag and take whatever she wants without permission, she would stare at me while we are walking instead of looking forward all the way which is uncomfortable. If I made a surprise to a friend, she would go and tell them and ruin the surprise and effort.
She would follow and chase me everywhere. She calls me her bff all the time when im around but when im not she would say bad things. sometimes she texts me just to tell me she loves me.
Whenever someone advice her she would reject the advice and she will act like she has done nothing wrong, or like nothing happened in every time.
No one likes her because most of the time she hurt others with her words but in same time they pity her. no one knows if this is her personality or she has some kind of illness.
And this is the part where i struggle with, I cant handle the bad things she says to me and i cant handle her stalking or her twisted personality.
For 2 months I tried to be okay with it but i reached to the point where i cant look in her eyes anymore.

My sister and my best friend advised me to stop her and tell her that i dont want anything to do with her but I cant do something like that. A few days ago, this girl sent a text saying she loves me and my sis encouraged me to stop her now, i typed "Please leave me alone" but i couldn't press send so my sis took the phone and sent it. but even though i did that, and she read it but she acted like it was nothing and acted like she always do. I don't know what should i do anymore .