He nods, unsurprised. He will simply have to be careful, then. 

"Will it make me any younger than I now appear, or will I simply cease aging at this point?" he asks to fill the time while he composes a suitably tight wording for his next real question.

"Making you younger would be a separate thing."

"Yes, I thought that might be the case."

And is it not convenient that there will apparently be nothing to tell him whether either part of the deal has actually taken place, until he notices either that he continues to age or that he does not, which will take six months at an absolute minimum. 

Now for the most important questions.

"Does the bargaining away of my soul make any difference to what will occur if I do, in fact, die of causes other than old age?"

A careful question deserves a careful answer. "Yes."

Jeremiah resists the urge to sigh, reminding himself that it would not be helpful.

"What changes result?" he asks with studied patience. 

"You go to wherever your soul is already, instead of your destination being determined by your soul's quality."

Interesting. That implies that Evanathe at least believes in the existence of multiple afterlives, with one's destination determined by one's morality, even if she does not have any more conclusive evidence than the Church. 

"So when I die, I will find myself in Fairyland?" he checks.

"Unless I get bored and send your soul somewhere else."

"Where else might you send it?" he wonders.

The question is apparently an idle one, but if the answer, or one of the answers, is 'Hell', he will use that as an excuse to call off the deal immediately. 

Shrug. "Depends who's offering what. I know a couple angels who collect odds and ends."

More suspiciously vague answers. 

"So Heaven is one possibility? What about Hell, or even here on Earth?"

"Demons are kinda prickly. Hard to make a good deal with. And mortals are... well, no offense, but you're mostly boring."

"Oh, none taken," he says with a grin.

"You are easily the most interesting person with whom I have spoken in the past decade, and I very much doubt that a random selection could produce one of the most interesting faeries, which suggests that your kind are collectively far more interesting than we mortals."

He's flattering her, but it has the benefit of being true. 

"I am willing to make the deal, on one condition," he says, clasping his hands behind his back so that she will not see them shake.

"And what's that?"

The wording of this has to be the most careful he has ever been. He must communicate his true intent clearly and exactly, not leaving Evanathe any space in which to obey the letter of his condition while violating the spirit. At the same time, he must not offend her by seeming to give orders. 

"I must ask that you are not responsible, directly or indirectly, for causing my soul to be in Hell at any time, so far as you have power to prevent this."

She looks at him consideringly for a moment, as if gauging his resolve, then nods.

"Very well."

"Then I believe we are agreed: my soul in exchange for immortality, subject to the aforementioned condition."

He holds out a hand for her to shake, not knowing how faeries seal bargains but hoping that the meaning of the gesture will be conveyed.

She takes his hand and smiles, pulling air past his ears to create a whooshing noise.

...he feels no different.

He thought he would at least be able to notice that he suddenly lacked a fundamental part of himself, even if he was correct in the conjecture that he possessed a less great soul than some. But he feels as though absolutely nothing has changed.

"Is - is it done?" he asks, voice cracking. She said that she could tell whether a person had a soul by attempting to take it - 

"Oh, yes," she says, doing her best attempt at 'unsettling smile'.

"Oh."

He - had a soul. And now he does not. 

He is immortal, assuming that the faerie did not cheat him, but - he had a soul. He had a soul and traded it away for a better chance - not even certainty - of escaping damnation. And yet, in doing so, he has surely damned himself irrevocably.

What was he thinking? Clearly the faerie bewitched him, convinced him that she was trustworthy, just enough, just for long enough to make the bargain. And now she stands there gloating - grinning - he wants her gone, wants to be alone and safe again so that he can mourn his lost soul in peace - 

And a smiling minute later, she disappears without a trace.

Ha, yeah, that was totally worth it.

He stands there for a long time, staring at the empty space where the faerie was, not quite believing that she is truly gone.

When nothing inexplicably animates, and no mocking laughter fills the air, he eventually moves, stumbling backwards until his hand catches the edge of his desk and he can slide down it to curl up on the floor and sob.

He stays there for hours. It's not comfortable. He is too exhausted and wrung-out to care.

Finally, as dawn begins to lighten the sky outside, he sleeps.