Some of the people at stalls are women; there's a little sewing shop behind one of the stalls, with a sign out front that says 'mending and tailoring', with a woman visible indoors; there are lots of women gathered in the occasionally shady courtyard, spinning and talking.

Step one, Keltham will cast Abadar's Truthtelling on himself, because he can't do that and also 'maintain concentration' as Keltham now has considerable practice doing; there's something about magical casting specifically that interferes with 'concentration'.

Step two, Keltham uses his Detect Thoughts scroll, purchased in Absalom; he did bring his scrolls with himself, through his flight from Cheliax.

Obviously he is most certainly not trying to detect anyone's actual thoughts, but Keltham does want to look around and take note of who are the highest-Intelligence women present, in his range of vision, and mark their Intelligence levels generally.

6, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 11, 11, 11, 12, 12, 13, 14. The 14 is one of the women in a shady courtyard spinning; so is the 6. 

He'll mark the 6, a 10 who's not in the courtyard, and everyone 12 or above, if they have any distinguishing features other than their faces that Keltham can use to so mark them.

Step three, test his approach on one individual before he potentially ruins the whole courtyard with a poor approach.

Over to the 10-INT who's not in the courtyard, first.  "Hey, I've got a truthspell up in hopes I can say some strange things and have them be credible.  In particular, that I'm a cleric of Abadar from outside Osirion, I have no romantic or sexual or generally harmful intentions towards you, and I want to pay you a gold piece solely to ask you some weird questions about your personal political opinions, which will be kept anonymous and not otherwise associated to you.  Sound reasonable so far?"

She takes a step back from him, a little suspiciously. "- yes, cicerone?"

Keltham will pass over the gold piece, putting it down a safe distance from her.  "I'd like to ask those questions of you later, actually, because I want to set up this survey with some others before my truthspell runs out."

"If hypothetically I were to say under truthspell that I'm from entirely outside Golarion, and that the questions I want to ask you are geared to making sure that I don't harm Golarion in the course of trying to teach things to Osirion to repay a debt I owe to Abadar - would that still work for you, or would you conclude that the truthspell was broken?"

"Well, it's strange that you look human if you're from another planet. I thought the things from other planets had eyes on stalks, and lots of legs, that kind of thing."

"An excellent point!  My current working theory is that humans here were grabbed from, or just arrived from, my home planet at some point a few millennia back.  I mean, if I arrived here, so could others.  The primary alternative theory would be that reality is very very very large and if you look far enough, you can find other places containing basically humans despite the lack of any common ancestry."

"How about if, hypothetically, I said that the godwar three months ago was over me and broke out two days after I arrived in Golarion?"

Blink blink blink. "I....think maybe you should be talking to somebody important? I could take you to a temple."

"That's already been done, more or less, and now I'm going around talking to ordinary citizens in Sothis to see if I would be doing this world a disservice by helping Osirion to become more powerful or more productive than other countries.  You would not want to do that with, say, Cheliax, and I am trying to see whether anything less dramatically horrible than that is wrong with Osirion, which I ought to ask their government to correct before helping them too much."

"Anyways, it sounds like the basic facts of the matter aren't too out of place for Golarion?  So I'll be back in a bit, once I've said the basic points to others under truthspell before the truthspell runs out, if that's okay."

"....yes, cicerone?"

"Or actually, to be clear, I might have a whole conversation with somebody else before coming back.  Hopefully one gp is enough to make up for the inconvenience there."

Keltham will now try to repeat this setup conversation on the smartest woman not inside the courtyard!  Does it go any differently a second time?

Nope, about the same! All of these people seem not totally able to keep up with the pace at which he speaks but able to catch the basics like that he's a weird important alien priest of Abadar who wants to ask them questions.

On to the courtyard, then.

"Hi, I'm a cleric of Abadar from entirely outside Golarion, who owes a debt to Abadar that, as I understand it, Abadar wants me to repay by teaching knowledge to Osirion."

"I want to check I'm not going to harm the rest of Golarion by teaching Osirion - the way someone would be harming Golarion if they taught say Cheliax - or if there's anything I should be asking Osirion's government to promise to change, before I start teaching them.  To that end, I'd like to pay several of you one gold piece each, to share your frank political opinions with me.  I will have some of that conversation via Message, with each such person, in case any of you have things to say they don't want overheard because of social non-accuracy incentives.  I won't pass on those opinions in a way that associates them to you, and have been promised various obvious things by Abadar's Church about nobody else trying to figure out who said them.  That's all the gold piece is payment for, and I do not seek anything else from you, nor seek to harm you in any way."

They stare. 

"Say that again slower, young man, my hearing's not what it used to be," one of the older women says firmly.

He can do that.

Everyone else is looking to her for judgment. 

She frowns. 

"Well, I suppose that's all right, so long as you're going to take your ideas to someone wise in the church and not do anything foolish."

"I was planning to talk to whoever Osirion's government sends me; I did not specify that they be a priest of Abadar, and cannot promise you that I'll only talk to members of the government who are."

"As for my not doing anything foolish, I'm afraid it's way way way too late for that, but I am currently planning to try somewhat harder at not being stupid in the future."

"....well, I'll pray for you to find wisdom and have all your big plans turn out all right. You just have to trust that things will come to you."

"Oh, I definitely trust things will be coming to me.  Good things is a whole different question."

"Any key questions that anybody wants to ask me while I've still got this truthspell up?  I haven't lied to anybody since I got to Golarion - as my own people define lying, intentional falsehoods told to create false beliefs other than temporary ones not meant to be exploited, jokes don't count nor misleading truths - and I wasn't planning to start in the next hour.  But there might still be things you'd want to check while the truthspell lasts?"

They mostly stare. 

"So you're not looking to get married?" one woman about his age asks.

"I've got no idea what your local standards are like for romantic catastrophes, but I'm currently recovering from one that's plausibly worse along several dimensions than literally anything that I would've expected to have happened on my own higher-functioning home planet in the last year.  So, not in the immediate future, no."

"Well, young man, we are more than the worst mistakes we've ever made. ...so long as you're supporting the children."

Keltham will not answer that; there are thoughts and considerations here that he would not wish to make their way back to Cheliax.

"It is in fact possible to make romantic mistakes of greater scope than that, and end up in relationship dramas affecting the whole planet.  But those details are not something I'd really like to talk about today."

"Any other questions?"

No other questions!