Hmmmm 🤔 I really hope they just keep their distance romance-wise, he doesn't really seem to be interested in her romantically(or anyone really if he hasn't married or been in a relationship in the last 143 years I forgot the number), I just think he's never been uhh coached not to be so forward or about social boundaries? If that's the phrase or maybe it's just the etiquette or customs of the kingdom? BUT I do agree, he's being WAY TOO forward in kissing her hand like that. SHE'S A BABY COMPARED TO HIM RN.
If I remember correctly I think Fiara is a reincarnation of a Japanese woman(it's been so long since I last re-read this XD) But she has some major saviour/idolization image of Zack for taking her in like *snap* right after she decides to live on her own and he like provides her with everything she's never been given by her family. I really didn't like how she's just given things right before she's seen to be able to do things for herself and how freaking fast their relationship moved like WTF?!, but let's see how the author takes this.
Idk I haven't read so much into the raws on the site where the LN is posted because google translate makes my head hurt. XD I don't remember reading all this closeness in the LN. BUT I COULD BE WRONG, lol just take my rambling with a grain of salt. Thanks for the translations!