Every week, you need to visit him in your room to boost up romance points. From there on, make sure to get every Historian secret (there's three of them) and choose to forget marriage and romance altogether at the Matchmaker's meetings. Those should help you get on his path eventually.
Viewing post in Who is your favorite romance?
Yeah, like I said, I did do that (but not the Historian secrets, I mentioned that too. I've also read that they're technically optional??? On other places of the forum since I posted this. Though to be fair I've sussed out that for Jasper's romance endings it MAYBE goes something like Worst/Not Very Happy [no Historian Secrets]; Married but strained because Jasper never fully opens up to MC [w Historian Secrets??]; and Happy Jasper End [w all four Legendary Endings between the kingdoms, idk if Historian Secrets make a difference or not.)
I was thinking that maybe I made some wrong conversation choices in weeks 4-6 to make me miss enough points, because I also got a perfect acquittal for Imogan figuring that also might help, but that wasn't enough.
List of what I DID do:
- Friendly Intro, Invite Jasper/Ria/Sayra for Breakfast, Invite him to First Event, Asked him to investigate the note [option three], "Explore" my Room once each Week I could, Compromised with Jasper and Hamin, Picked "People are terrible, Jasper", Chose no marriage or romance at the final Matchmaker interview, have good relationships with Ria and Sayra, got perfect Acquittal for Imogen, and got 2/4 Legendary Endings (Peace for Revaire, and for the Jiyel/Arland conflict)
So yeah, I'm thinking other than the Historian secrets I got some dialogue options wrong further down the line. Do you remember what you picked?