How to ask. A girl to homecoming?

Ok theres this girl i like but she has an 8 th grade boyfriend ( were in ninth grade) but i wanna know a sure fire way to have her say yes to go to homecoming with me were good friends and ice been tryin to throw hints at her that i lile her and i think she picked tem up and i think she likes me back a little but any advice woyld be nice becuz i reall really like her thanks