What are the nuances between くれますか vs くれませんか in terms of requests?


I know there are more politer forms like itadaku but just focusing on the masu
and masen aspects, which is politer? What are the nuances? Which is more
forceful-sounding?




As so often, it depends on the context.

Just translating them into English should be enough of a clue. 「～くれますか」 is
simply "Will you give me ～?" (or "Will you do ～ for me?" in the case of
「～てくれますか」). 「～くれませんか」 is simply "Will you not give/do for me ～?", which of
course can be rearranged to be "Won't you give/do for me ～?"

I would say that more often than not, ～くれませんか is a little softer because it is
more like you're politely asking for help with something, and ～くれますか is more
straightforward and blunt. But again, depending on context, different meanings
can come across. If your friend asks you

> ￥1000貸してくれない？ → Won't you lend me ￥1000? (= "Can I borrow ￥1000?")

they are asking a favour of you. But if your boss asks you

> 17:00までに書類を揃えといてくれない？ → Won't you prepare the documents for me by 17:00?

s/he's obviously not asking you to do them a favour; it's a very polite and
indirect command.

Now if you substituted くれる into both these sentences, they'd have a completely
different feel. "Are you going to do ～ for me?" This sounds less amicable,
like the asker just wants to know the facts. It could even convey a bit of
annoyance of unmet expectations. ("Are you going to lend me the money (or
not)?", "Are you going to prepare the documents (you lazy worker)?")

* * *

Lastly, just to note, the polite (respectful) form of くれる is **_not_** いただく;
it is くださる. いただく is the polite (humble) form of もらう. Refer to [this
post](https://japanese.stackexchange.com/q/402/78) for more information on
those.

