Kaze no Stigma

Katherine McDonalds challenges Ayano to a fight. While awaiting for the day of the fight Katherine hires Kazuma to be her coach, and falls in love with him. As a result, Katherine makes a proposal to Ayano: if she wins, she takes Kazuma back to America with her, and if she loses, he stays. Ayano ends up winning, but Katherine decides to stay anyways.