"You're absolutely right that people will, and should, take into account the chance you will break a promise! That's why we're not supposed to ever do it outside of wildly unrealistic thought experiments! But we can't just decide to make that chance zero. We can try not to do it ourselves, but we can't promise people that paladins are literally incapable of breaking promises."
"In practice, paladins Fall due to mistakes, by taking tradeoffs that they absolutely should not have taken, by being broken, or just by - deciding, or rather finding out, that they don't care as much about what all the paladins in the world can do, as they do about saving the people suffering right in front of them. It's very, very rare, but it's known to happen. I don't think that - allowing the theoretical case of correctly deciding to Fall, which is still theoretical even for us right now, adds much to that existing uncertainty."
"If you need a truly absolute guarantee, you have to get a promise directly from a god. Most people can't afford to talk to the gods, even through their clerics, and - obviously I'm a poor substitute for Iomedae. But it's what we have."
"You are also correct that trading with Lawful gods is better, all else being equal. That is, in fact a reason, some gods choose to be Lawful - Iomedae explicitly considered it, and recommended it to others, and for all I know some of the ancient gods might have made that decision deliberately as well."
"And - the gods already choose the mortals best suited to be paladins. Those who hope to be chosen should strive to be the best candidates they can, including in never breaking promises or even contemplating breaking them. I think what I'm describing is, if not absolutely unavoidable, then at least the best thing that can be achieved in practice with mortals. We don't often ask the gods how we should change our teachings, but we do do it sometimes, over the centuries, and we also consult summoned Lawful Good outsiders, who are not as wise as the gods but often wiser than we are. And Iomedae confirmed some of this during her life, talking to Aroden, and after Her ascension She did not tell us she had been wrong. So I expect that if we're wrong about this, it's not to a very harmful degree."
"I think - though I wasn't taught this explicitly and may be wrong - that there are two reasons we teach new paladins that it's theoretically permissible to break their word."
"If we told them they're expected to categorically never Fall, that they'll be held to a standard of perfection, it would be - unhealthy for them. They would judge themselves harshly for the very human impulse of even wanting to do some Good that would break an oath. They wouldn't understand why one might consider making such a tradeoff; and later, faced with a terrible temptation, they would not know the correct argument that this particular tradeoff isn't worth it. They would think the temptation threatened their virtue, instead of their reason. And that - probably ends in more paladins Falling to temptation."
"And if we told everyone else that paladins categorically never Fall, then most people wouldn't believe us. They would hear of paladins Falling in a few historical cases - which is true - and think us conceited, or arrogant, or foolish, or worst of all lying, pretending to a higher virtue than we possess, even if we carefully said only what was true."
"So we teach new paladins - as I was taught - that such tradeoffs are possible, because it follows from the general case that most things are tradeoffs, that we ultimately seek Good and paladins oaths are not in themselves a crucial piece of Good. We teach them that the gods may, in fact, make such tradeoffs, because They are very wise and very knowledgeable. And that they should never make such tradeoffs, just as they shouldn't expect to personally slay Tar-Baphon, and just as it was terrible and culpable foolishness for some paladins to attack Geb. And we tell everyone else that paladins sometimes Fall - always regrettably, often tragically, and not ever because they made the right tradeoff - but it's something of a mitigating virtue, to be seen as Falling because you foolishly thought you were saving everyone in Hell, rather than because you foolishly believed a demon's illusion, even though these might be two ways of describing the same event."
"I'm not sure how to reason about Milliways. Perhaps, if the criterion is whether you'll have a fight, then you could have been - superhumanly convincing and made him open the door anyway. Or perhaps, instead not giving Gord access to you because you would attack him, Milliways would not give you access to Gord, and instead would give you someone who would agree to let you into Golarion. But I'm - really confused about how this logic works and I don't want to speculate."
"As for following orders, I can't speak to your personal situation. But to fight our wars we have had to have armies, and other organizations like paladin orders, and even governments. All of these have people swear to follow lawful orders, within the scope of their mission. And even ordinary laws involve sometimes ordering people to pay a fine, or otherwise to do or to stop doing something, and being a member of a society with laws means promising to obey such orders."
"A lawful order need not be Evil, for someone to decide they would rather break their Law than follow it. Here is an example." (She is so glad she went to Vigil! She got the chance to learn the Lawful side of paladinhood from the best, even if it was mostly self-study in the public libraries and then a few rushed weeks with the order that hosted her.)
"A family is divided by conflict. Two brothers live in different countries that make war on each other. Both honestly believe their side of the war is right, and freely chose to fight for it. But when they come face to face with each other in battle, they find that they would rather break their oaths to serve than kill each other. Both are hung as traitors, each by their own army."
"The orders to fight another army and kill its soldiers were Lawful, and not Evil. But they were not Lawful Good, because two Lawful Good armies wouldn't fight each other, and if for some very surprising reason they did, they would - or at least should aspire to - recognize that two soldiers mutually recusing themselves from the order of battle was a better tradeoff than not doing that, and so they would not condemn them for it."