S.H.
They don't have to be friends.
But teach your daughter, that being mean is not the way.
It is harder, because the other girl, will not leave her alone.
Children, are fickle and change and change friends.
This is also normal.
But if another child will not leave another child alone, then out of 'frustration', the child (yours in this case) may resort to mean-ness... in order to get away.
Children are not experts, at 'coping-skills' or social conundrums.
Perhaps talk to the teacher... since this is becoming disruptive and causing your daughter to be... very frustrated.
Even if she is sensitive to other peoples feelings... (even for adults), if a person does not leave you alone... then frustration/anger occurs.
For an adult though, they have more skills, to deal with this. We simply have more years and development to get more astute at it.
For a 7 year old, they don't.
The "American Girl" book series, is GOOD.
You can find it anywhere, even online like at Amazon, Barnes and Noble, and E-bay.
They have one about friends.
ALL children... change and their friends and interests.
The thing is... to guide our children, in how to manage, that.
Even talking to the Teacher, for ideas or assistance.
Afterall, you wouldn't want your daughter to get into trouble... over this.
But if that other girl keeps not leaving her alone... then, what can she do???
It would irk even a patient adult.
If your daughter does not want to be friends with the other girl anymore, fine.
Talk with your daughter about it. Not lecturing or judging her. But let her... talk about it and express it.
She needs an outlet.... all kids do. And we Mommies, are the soft place to fall... for our children. No matter what their issues, are.
I would never, force my kids to be friends with someone they don't want to be friends with.
But they can be civil.
Even adults, we wouldn't want to be friends with someone we just don't want to be friends, with.
A child, needs to know themselves. And this... is one part of it. Finding out, who they are and their cues.
But guide the child.
Your daughter seems VERY frustrated by all of this.
I feel, sad for her.
A 7 year old, can't just deal with this on her own. And it is making her... very angry and negative.
But she needs to... be, kind.
She seems to me, to be not able to cope. With this and the other girl.