Trouble with the word "ni"
Does "ni" mean "you" (plural) or is it just a formal way of saying "you"?
I would really recommend not using "ni" when speaking to one person. You cannot be sure if it will be received as more or less polite than "du". You can say "du" to anyone, maybe except for the king whom you should simply call "kungen" ("the king") if you want to please the court.