Okay one shot/prompt idea, so you know hanahaki disease and how if affects people who are victims of unrequited love but what if they just couldn’t believe it was requited So a person so hopelessly in love with their partner but they have such low self esteem that they simple can’t believe that this amazing beautiful human loves them back and so they end up developing hanahaki because even though it is requited they just can’t believe that. You’d end up getting this really depressing story of a couple so ridiculously in love with each other but one can’t believe/understand and ends up dying.
OOOO or you could do it of having a widow or something and develops hanahaki because their partner is dead and so their love is now one-sided and they end up suffering alone because nothing can fix it