"If you're currently desperately trying to figure out how to pass an implied loyalty test or tell me something you think I want to hear, you should possibly just skip that part and blurt out whatever it is you imagine will offend me. I have sufficient Sense Motive that it's not overwhelmingly likely to work. And yes, it has already occurred to me that if you don't remember being a priestess of Asmodeus, or possibly even genuinely never were one of our priestesses, you may perhaps regard our interests as not being entirely aligned and specifically with respect to a message successfully reaching Cheliax and a Gate opening from there to here."
"If you were a priestess of Asmodeus, you're damned for what you've done regardless of what you do or don't remember, and it will not be in your interest to someday arrive in Hell with memories of working against Hell's interests. In that case we are, in fact, entirely aligned in our true incentives."
"And if you never were one of us, then you're genuinely from a place that has a truly impressive amount of Law. Unless I determined that I could get what I wanted out of you without your preferences mattering at all, so long you had greater than zero negotiating power, we'd cut a deal.* There were multiple countries holding the Worldwound border, and both Mariona and I dealt with opposed alignments and countries Lawfully under the Worldwound Treaty; that, too, was a requirement of our jobs. If you've already figured out how to get a message to Cheliax, you can, for example, offer that to me conditional on my signing a deal that the Gate only picks up myself, and I pay for Cheliax to leave you an item that does food and water purification before I depart. As would leave you in a moderately better-off condition than if I stay here and lose my cleric powers. I'd be reluctant to leave you behind if you were my real Mariona, but if Cheliax says they know where she is and she's not here, I'd go along with it."
(*) Esta is leaving out, not really letting himself be conscious that Merrin might not already know it, the part where only a small amount of negotiating power might result in a quite unfavorable-seeming deal. The difference between Asmodeus and Abadar is not that Asmodeus won't offer you a compact that leaves you and He both better off than with no compact; Asmodeus loves that part nearly as much as Abadar. The difference between the two gods is that, if Asmodeus is stronger than you and has asymmetrically much more threat to hold over you, He will consider His baseline and BATNA to be 'I hurt you until you obey, since you can't hurt Me back', and the compact is about you and He both doing better than that.