In Quinncoru, Kiri - with Aleko in tow this time in addition to Renny - makes a visit to the palace, and, since the king seems willing to ignore her and she doesn't really want his attention, and since there is not a full complement of primes around, has nothing much to do with herself but make a beeline for the prince. (Aleko goes exploring by himself.)
Okay, a queen's permission should work as well as anyone else's. Kiri brings the letter to the elder prince's room.
"Hi!" She considers sitting on the arm of his chair, decides that this is hazardous, and instead hands him the letter and leans on the chair instead.
"Yeah, it doesn't make a lot of practical difference why she's sending you as long as it'll stick."
It makes some amount of difference to the prince's life that Queen Risella is the sort of person who accepts invitations on his behalf without consulting him—but not a lot of difference, because there aren't that many occasions when she can actually exert influence over his life, and even fewer where she cares to. And in this particular case, she's doing him a favour by it. No doubt the king was much more receptive to whatever she said about it than he would have been to the letter alone.
(Leaving aside the fact that 'nice' can mean a lot of things, and a lot of words can mean this thing, if they're the word that he says when he means it—)
The thing that he meant when he said that goes something like this: she is good to have around, someone he doesn't mind talking to, someone who doesn't want to hurt him, someone who sometimes does helpful things. Someone he likes and cares about, who gives him happy feelings.
"Are you going to have to bring your tutors, do you suppose? The house has the loveliest library of course, but I don't know if you'd be obliged to take them along anyway."
"It's a really nice library. I'm glad we're the family with all the libraries, I'd be so bored if I had to run a million acres of farms like Alser."
"I guess! And he seems to like it all right, and I suppose he has people for it, the way I don't have to personally run any libraries unless I feel like it."
"I inherited a lot of stuff. It's got people looking after it, but I don't just want to ignore it. And I have my brothers to pay attention to and my mind to figure out and I have to be here sometimes and occasionally I still show up at school although it might make sense to just hire me a tutor, I could share with Aleko and maybe even Jayce - Renny and Karls won't hear of me doing only self-study, not before I'm at least twelve, so it'd have to be a tutor if it was to replace school - and I have a lot of stuff to learn about being prime so I have to do that too."