i don't think the process of him bullying her when they were young kids was shown much, rather that he made the whole class point and laugh at her for crying because of what he was doing to her, that he was constantly making her cry deliberately, he was only doing it to her and then when she would cry he would berate her further. i don't see why on an app that targets kids there needs to be a promoted cash-grab story which depicts the character "falling in love" with someone who gave her a long-lasting trauma. the bully saying stuff like "i can't change on my own" and explaining that he targeted her because he "loved" her or whatever is not at all a good message to put out there and doesn't show the character development you speak of.