@lalalas2,
Here, I'll translate into English.
You feel like an outcast at school and sometimes a popular girl takes pity on you and you wonder if she might be interested in you somehow.
She's being nice when it is convenient for her. So consider what that means in terms of her character.
School will end, and you won't have to see any of those people ever again. Most of us have far better lives once we finish high school. Already done with high school? Then find a way to get out of your town. Get education in some field where you can work elsewhere and then go. Meet new people and experience a different part of the world, even if it ends up being another small town. And yes, even if you don't get the best pay or perks.
Just, be away. And your life will improve.
Life is still not improving? Then seek out counseling and go. Learn how to raise your self-esteem by yourself, and do not be dependent on others to do so. It is not their job.