Seldan looks at him, and - doesn't think "I Choose you" because for some reason that word is upsetting, but the mental motion doesn't need words -
- it's like falling into blue, and for a moment a glimpse of interwoven threads that might be the structure of Foresight itself as perceived directly by Seldan...
Seldan loves him, though right now it's mostly still in an abstract way that Seldan himself is faintly puzzled by and poking at curiously, exploring what the Companion-bond is like from this end — what a fascinating implementation, and what an odd world they live in, where the cheapest friendly intervention a god could provide was to reincarnate a dead man as a magic Mindspeaking horse and glue his soul to someone important, what does that imply about the gods and how They work...
Seldan has absolutely no doubt that Blai is important. He may not know what Blai has been thinking, or the intricate details of what motivates him (though he's eager to know, for Blai to make sense to him, for the intriguing glimpses he's caught to fit together) but he wasn't shy about getting the run-down from some of the other Companions about what Blai has been doing since he arrived in Velgarth a few days ago.
Which is behaving exactly like a Herald. He landed in a strange world and immediately fought a monster and saved a little girl's life. He was kidnapped by an archmage everyone had been telling him was evil, and still tried everything he could to head off a war. It almost doesn't matter what he was thinking - it matters to Seldan, of course, because Seldan loves to know the complex machinery behind anyone's decisions and the bond has taken that and run with it - but, ultimately, the thing it most makes sense to judge someone on is their actions.
(Flickers of a remembered debate over whether it changes the moral valence of someone's heroic act if they did it for selfish reasons, though he hasn't the faintest idea who he once debated that with and one assumes they died centuries ago.)
Blai was heroic but, more to the point, he was careful, and Seldan respects that a lot more. There's an incredibly difficult balancing act, when acting under uncertainty, of living in the various possible worlds at once, rather than collapsing confusion into one interpretation, and his sense from Enara that Blai did this rather better than most of the Heralds in Haven. There's an even more difficult balancing act of - he thinks of it as living in all the possible worlds, and considering not just how your decisions affect the concrete physical details in front of you, but how the rules behind your decisions affect what the possible worlds are, and he sees flickers of that in Blai, too.
Maybe most importantly, Blai is not an overawed teenager waiting for their Companion to mold them into a virtuous adult. That's not a bad way for someone to be and it makes sense that it's how most Heralds start out, but - Seldan is not sure he would be good at it. Which is presumably related to why he's been pointed here instead. Blai was already doing all of that, without anyone guiding him (except maybe the concept of his goddess but it's not like she was there giving orders). Seldan wants to know everything about Blai's life and Blai's world and Blai's goddess, and then - well, they're kind of still in the middle of a crisis here, aren't they, and he wants to help.