I'm not going to allow a toxic girl to sit next to me on a school bus
Does she want to sit beside you?
I heard that she wants to sit beside me.
If this person is really toxic then you have the right to refuse her to sit next to you. If she sits next to you then you should move let her know the seat was taken.
It's none of your business.
It's good to not want to be around toxic people. Just make sure you are polite to her and if all of the other seats are taken, open a book and focus on reading rather than talking to her.