@Starbright thinks MC betrayed her bc he dumped her amidst of their date in Ch. 14. She obsesses with MC bc he was nice to her once and thinks she can control him, as he is a weak and emotionally destitute cherry boy. Bc of being the school's idol, honors' student and class president, everyone listens and obeys to her tantrums. A perfect recipe for a disaster.
She already snapped once, when MC defended the, atm, nameless JK and as a consequence, she told some guys about the rumors, almost provoking a gangrape scenario if not for MC, after that, she gave him the cold shoulder for weeks. Tbf, she didn't like him as a person, but bc what he represented him to her: a weak soiboy who can be manipulated and tamed bc the other boys were "scary and not like her daddy" in her eyes. Now that MC broke free from her manipulation radius and was being honest with himself, she showed her true colors.