"...I, er, I'm not sure I know exactly what you mean by 'Law' there."
It feels like it's - something deeper than just 'will follow Valdemar's laws' which obviously wouldn't be sufficient to convince Leareth to come to Valdemar for face-to-face talks???
"I - do think his trust in our, er, integrity, has generally not been the limiting factor here? I don't trust him enough to want to meet him face to face," where he could cast compulsions on everyone, assuming of course that he can't trivially do that at a distance or by showing up under illusions but Vanyel is, mostly, assuming he can't do that or at least that it would be very costly for him not to be detected.
"- If I'm trying to imagine his objections, I - think they would be that it doesn't matter what we say, we're a country that follows the gods - and our Companions are direct godmiracles," influenced by it in ways Vanyel knows better than anyone else and also incredibly does not want to talk about right now, "and he doesn't trust Them."