Wait until six-year timeskip, then marry her, MC-kun. she really wants your children in her womb it's such a shame Hisui was destined to be a losing heroine from the start.
very persistent.....tho, she doesn't seem to consider what Isshiki's real feelings and thought are....brute forcing her way without pausing to reflect/think about the consequences of her actions would led for a very bad time....