It was so lovely that I didn't want to potentially shit up such a nice scene and ruin it for anyone with some fridge logic thoughts on this and the problems I see with it. Nothing negative, necessarily, mind you, but it could ruin the afterglow of the sugary sweetness you just witnessed.
...How the hell was Lily able to know all this? I mean, okay, she's blind. She could easily have enhanced senses of smell, hearing, ect. But how did she know that Heath was the monster? Specifically THE monster? Lily being able to tell Heath was lying is extremely believable. And she's probably gotten good at reading people from subtle hints. Like how Heath was anxious and lying in order to tell her stories to be with her. That makes sense. Buuuuut... That doesn't tell you anything that the person isn't human. Or just so happens to be one inhuman monster among multiple (Heath herself said OTHER monsters called her a failure, so others exist, she's not a one off... after all something had to have birthed her) that ~20 years ago burned down your home town while you were still in the womb. When Heath offered Lily her hand, she wore thick gloves. Maybe Lily was able to tell the structure of the hand was... off. Maybe that would be able to tell her "Hey, Heath ain't human." Okay, granted. That makes sense. But, again, how does that tell you that Heath, SPECIFICALLY, is that same monster? Kinda a huge assumption there and kinda a stretch for Lily to say she "knew." Maybe, JUST MAYBE, suspected it as a possibility, but... Any more than that is really stretching it. Unless I missed something.
It's surprisingly kind of nice and is able to be emotional without feeling really forced. Nothing can ruin a mood more than when a story tries to have an emotional scene but it just fails. I do kind of hope Lily, Will regain her vision though. I thought maybe this will be some Beauty & The Beast stuff with Lily regaining her vision after they both confess.