Or a majority, since the alternative is everyone being damned to CE.

We could always cut our throats. 

Okay.

Different tack, from the top:

He did assume she was his ally, yes, because they want the same thing: the safety and security of the Korvosan people. 

She also cares about their well-being.

And increasing the influence of Hell in the Vault can only improve Korvosan well-being - if you take a longer view than the next five minutes of Prime Material life - if it's necessary and sufficient for them to survive the shadows with only a minority becoming damned.

He did assume she was his ally, yes, because they've worked together in the past to secure the safety and the well-being of the Korvosan people. And now she's going to betray him?

That's hurtful.

That's why she's giving him the heads-up! She doesn't want him to feel, at the very least, like she's sticking the knife in his back.

I feel like you're just slightly out of character in that last tag: remember that you haven't had the experience of me trying the earlier tacks, so there's no preexisting frustration with me, and that I can convincingly look sincerely shocked and wounded, so you shouldn't feel annoyed that I'm cynically accusing you of betrayal in a calculated ploy. 

Oh, that's true, my bad.

How convincingly sincere are we talking here?

My bluff is +11 from ranks, +3 class skill (Trickery domain), +3 charisma, +3 Circlet of Persuasion, +5 because "the target wants to believe you", sums to +25.

What's your Sense Motive?

+11 from ranks, +3 class skill, +5 wisdom, +1 Stern Gaze (Inquisitor), sums to +20.

So I'm favored but it'll come down to the dice, then.

I can't check what you'll roll before I decide my tack, but, pretend that it does work.

How do you respond?

From the top:

He did assume she was his ally, yes, because they've worked together in the past to secure the safety and the well-being of the Korvosan people. Now she's going to betray him?

I will always fight for the safety and well-being of the Korvosan people, and I count as an ally anyone else who's doing so. I don't want a fight with the church of Asmodeus, and that's mostly because it'd see shadows loosed in the Vault, but it's also because I hate violence, and - now that you've raised its salience in my mind - because it'd be a personal betrayal when we've worked together in the past and had mutual plans to work together in the future. I'm not going to sabotage Korvosa just to sabotage you, and I sincerely hope that we never act at cross purposes. I'm willing and ready to work on mutually desirous projects.

And I want you to know, because I find it exhausting to carry a sword behind my back and because I hate smiling when I don't mean it and because, now that you've raised its salience in my mind, you - who I've caused to believe are my ally - in particular deserve to know: I don't think that being damned is good for the well-being of Korvosans or anyone else, and if I don't injure myself to injure you for as long as we're fighting the same shadows and if I do things to increase your church's effectiveness as an institution (as long as it's affecting shadows and not effecting them), political considerations about your relative power will be the tie-breaking vote when I decide who to support and how, and also I don't consider myself above interacting with you in an Asmodean way.

That was clarifying, and it's probably the best that I'm going to get. Thank you, Field Marshall, for helping me to interact with you according to my own cultural customs and for helping that interaction go well according to my values.

She's always happy to help people understand her. If Reebs would care to reciprocate, while we're still safely inside this hypothetical conversation where accusations are siloed and no one loses face or has to posture if she asks, there are some questions she's wanted answers to for a while: 

What does Korvosa mean to you? Why do you protect it? 

Hm.

I feel affection for the convoluted laws; I love to read them and find the forgotten and overlooked ones and notice where they touch each other by accident and combine them all into legal arguments which I should never ever force an Arbiter to rule on. My journals are full of novel legal theories which will never see the light of day.

I enjoy my talks with Lord Ornelos; there is no such wizard in mainland Cheliax: the Thrunes have invented a new breed of wizard, one much less interesting to speak with. The culture in Korvosa agrees with me: They're Lawful because they prefer to be, and the Law takes care to keep them that way. They're Evil, but not beyond all reason and at the price of other interests. In Egorian, people are Evil to prove that they're Evil. Rotate this in your mind: they use wanton destructive cruelty as a costly signal of their dependability.

You'd think it blasphemy against Asmodeus. What morally Neutral man on the fence could see Egorian and take seriously our claim that to do Evil is a selfish advantage? But Asmodeus is Evil, and cares less whether we play well than whether we play to His advantage. Aroden said He would build Axis on Golarion, and Asmodeus said He'd build Hell, and while these great works progress, I appreciate that there's a place for me at their far periphery where... I can enjoy plotting petty revenge on a Caydenite gutter rat because my options have been constrained enough to make even that fun, but not so much constrained as to make it unbearably frustrating.

...And beyond those answers, Field Marshall, which serve my image and which you may have expected from me... I imagine that Korvosa means many of the same things to me that it does to you.

I love the crumbling conjured walls. I love the white sails of ships in the bay. I've come to tolerate the weather - I am human, Cressida. 

If you love Korvosa the way I do, why instead of serving it do you serve Hell?

Of late I serve both.

And when they conflict?

I sincerely hope I'll never have to choose between them.

But you do. Every day you have to choose between them.

When - when Lord Toff Ornelos dies, if Hell called you to witness against him, would you choose Hell? Or would you choose Korvosa? This isn't a hypothetical! Would you cast the maledict the thousands of people in this Vault who straddle the fence between Axis and Hell? Would you maledict your two-hundred clerics who've done you no wrong? Then why do you preach poison. 

This is a sincere question!

I don't know why you're doing it. 

Do you?

...I think we're just about done here.

nandwich, I didn't ask you to lend her my character model.

At the end of the day, she is a figment of your imagination.

Expect some character bleed.

Wait, one more question before we leave the hypothetical: were you being honest with me, when you said you were being dishonest with me, when you said you felt hurt and betrayed?

My bluff is +11 from ranks, +3 class skill (Trickery domain), +3 charisma, +3 Circlet of Persuasion, +0 because "the lie is believable", sums to +20.

My Sense Motive is +11 from ranks, +3 class skill, +4 wisdom, sums to +18.

Of all the hapless idiots on the face of the Worldeater's Cage, how could I possibly know?

...And in the interest of full disclosure, because he assumed that she was here as his ally and because she hates false pretenses, she is not herself thrilled about Asmodeus's influx of manpower and perceived moral authority.