We could have had it done last turn, but you kept pushing for Iridescent Toxin for some reason.
Past experiences have me not very trusting about people saying that we'll do things next, as it frequently doesn't happen.
Which is not a reflection upon you. I'm just quite wary about things right now.
We might have gotten a better deal with the Iron Fist, but we just didn't make any effort to learn basic Diplomacy.
Okay, so, one action
cannot get us Diplomacy 1. It's mathematically impossible. In order to get Diplomacy 1 before we completed that negotiation, we would have had to spend a minimum of 2 actions on it, almost certainly delaying the completion of the deal. Which, given the penalty we got to Face for it taking as long as it did, would not have been an improvement.
Indeed, given the bad first roll, no amount of Diplomacy short of 5 would have completed it quicker. Might have improved the deal in other ways, I suppose, but I'm not sure of that at all with something like Diplomacy 1.
Getting Diplomacy (or any skill at all) is always (well, until we hit, like Cultivation 15 or something like that) either a 'this is basically all our actions for a turn' or a multi-turn commitment. Which means you still have this problem even if we spend an action on it this turn, since that action does not, in fact, get us Diplomacy, it gets us only one action closer to have it...if you don't have faith in multi-turn planning that sucks, and I feel bad about that, but it also means we can't raise skills much at all unless we abandon doing much else for a turn.
Basically, any sort of coherent 'raise skills' plan has to play out over multiple turns unless we're going full 'closed door cultivation, nothing else occurs'. And even that would get us, like, maybe two levels of a single skill.