
I read some spoilers before
You know the king is the ML and that Nina is his lover she's being reincarnated or what kinda similar to Elizabeth in Seven deadly sins cause you can see in the early chapters the girl on the prison was actually her and the king was curse that's why it happens
Sorry the explanation was a mess lol

Nope, they are what I think you'd call "star crossed lovers" where Nina, in the beginning, was the lover the reincarnated in Korea then transmigrated into the book. BTW hopefully this helps you a little, there isn't any romance until Nina reaches adulthood. Plus the age gap isn't terrible (4 years) - it could be a lot worse like there's this novel I read that got turned into a manhwa but I don't remember the name, the emperor ML was like fucking mid 30ish and the FL was in her teens (THAT was disgusting age gap). The villain's name was like Rosemary or something and she had red hair so if anyone knows the name knows what story I'm talking about. Anyways at the moment, everyone views her either as a pet (ML) or a friendly cute girl (2nd ML Duke).

There are worse age gaps out there in popular novels and manhwa's that I haven't heard a single complaint about so I really don't understand a lot of people hating on this novel. I I mean Abandoned Empress has an age gap of 4 years just like this story, then there's Suddenly Became a Princess with Lucas being over 200 years old (I STILL LOVE U JUST KINDA CREEPED OUT) and Lady to Queen, with the king being mid 30ish and FL being in her teens (16 to 17 I think it was).
Honestly from the way things are going, Nina seems like she’s the future daughter of the king and the saintess, which would explain the hair and eye color similarity, plus why her holy power clashes with the saintess’. But I can’t really be sure, please put some spoilers below if you know