I like the idea that it was Cerise’s mother who really initiated things with Badwolf, considering the nature of the original fairytale.
My headcanon is that teenage Badwolf is gruff, rough & tough, but doesn’t like harrassing anyone but got a big bad rep from getting into fights with people who throw nasty comments his way or shove him (such as huntsmen or heroes trying to prove themselves early). Red initially totally believes he’s a villain, after all that’s what she was taught all her life, and tries to avoid him. Unbeknownst to her, he’s also avoiding her, because even when he walks past her in the hall some hero will try to pick a fight with him to ‘protect her’.
Eventually the two end up together by some twist of fate, maybe they both have the same favorite spot in the enchanted forest. They run into each other and he immediately goes to leave but she sees he honestly doesn’t want to bother her so she says she doesn’t mind if he stays. The two end up hitting it off and joke around a lot. They begin to be friends tho they know they cant hang out in public. They learn how to fake being enemies in public and they laugh about it in private.
Soon they both start to get romantic feelings for each other. Badwolf tries to be respectful and doesn’t want to act on them, but Red makes the first move happily. They decide they can try to be together despite their destinies, and fall passionately in love from there.