He really wants to ask this question of a different person, a person he can't find here no matter how hard he looks, the person she grows into when she's not mindread and when it's not safer to be small. She will of course genuinely try to extrapolate that person's answers, but there'll be pieces missing, in precisely the places where thoughts are too dangerous to think.
She doesn't actually know how good the Empire is, how much she cares if it falls to god-cult states, so long as enough remains for the god-project to commence somewhere out of the reach of the gods. It might be that it's much better than everywhere else, not just in - day to day standards of living, Altarrin talks about that, but in - potential for growth, potential to be a place where people can build Civilization to their own sensibilities. Most places aren't that, but it's a spectrum. It's ...not a spectrum along which the Empire looks particularly good. People can't change very much, when their minds are bound by magic.
She has no trouble believing the god-ruled places are even worse. After all, Cheliax was. But ...the Empire isn't very good in her view, just the least bad thing.
This doesn't mean she isn't sincere about wanting to trade with it. You can trade across even quite a gulf in priorities, and the Empire is clearly the kind of place - well, the Emperor is clearly the kind of person - you can trade with. Powerful wizards usually end up independent. They're hard for even a powerful ruler to truly control, and they want their own things. You don't become a powerful wizard if you aren't somewhat monomaniacally obsessed with some aspect of magic. Being an admirable powerful wizard, in the conception thereof in Carissa's heart, is being Lawful and possible to trade with, while you live in your wizard tower which rivals many nations in treasury and exports.
(Cheliax kept a handle on its. But - a loose handle, much less of a handle than Bastran has on Arbas for a lot of people of the same character - and only because they were soul-sold.)
She wouldn't betray Bastran; he had the chance and didn't betray her, because he saw in her that she would return his cooperation. There's complicated theories here but this really isn't complicated; it is the sort of thing where the shards of Law in humans pull the same way as the true Law. She'd take some risks for him, if he asked it, though not readily the risk of having her values and priorities distorted for the rest of time.
She's terrified of a compulsion that lays fine on everyone else but that catches the wrong edge of how Carissa sees the world. She can imagine laying waste to the whole world to strengthen his Empire, if she was bound to serve it as best she could and not able to lie to herself about whether a given plan did that. She's terrified too that he'll tell her he can't allow the god project, that he'll kill her if that's really what she means to do. She'll promise not to do it, in that case, and hold to the promise, but - it'll be so much lost forever.
She knows that if she were not afraid of him she would admire him, enjoy his company, enjoy surprising him. She is terrified of him, so this is an abstract feeling, sort of like a memory, though in fact in her memories of being Caris she was mostly trying to invent a new kind of sex on the spot rather than contemplating his character.
She did, sincerely and with uncomplicated intent, intend to love him, before, to memorize him and amuse him and accept him and surprise him and be a dozen lovers for him and bear him children; she doesn't think it makes sense to do that, now, not because she wouldn't if commanded but because he'd have to command it and she understands him enough to know that'd ruin it.