"See you at midnight."
Translation:Rendez-vous à minuit.
I think I get it……If for example we had already fixed a meeting for midnight, on leaving at the end at the conversation we could say 'a minnuit' as a parting phrase, but to actually arrange the meeting we would have to say 'render-vous a minnuit' (which is more like 'let's me at midnight' rather than' see you at midnight' as DL said) I totally get the 'rends-toi' explanation - thanks.
Actually it is more formal than it looks.
The more 'friendly' phrases, between friends would be: "Retrouve-moi à la gare à 4 heures" or "on se retrouve à la gare à 4 heures".
"Rends-toi à la gare" is imperative, like a command or an order and "se rendre" is more formal than "aller": "Va à la gare".
If you say (to a friend or anybody else) "Rendez-vous à la gare à 4 heures", it is the equivalent of "Go to the station at 4" or "Let's meet at the station at 4".
"Rendez-vous" in itself was so widely used that is now considered as a noun, and was probably used in a time where even between lovers you would use "vous". (You can even say "J'ai un rendez-vous chez le médecin demain" = "I have an appointment with the doctor tomorrow") The use of "vous" in the expression doesn't really have anything to do with formal or unformal speech anymore, so you guessed right!
I think it is because DL wants you to know how to say simply "see you at midnight". If you only learn how to say "I will see you at midnight" which is what your sentence says, the day someone says "à minuit", to you, you won't have a clue what they are talking about. So DL wants you to know the difference. It is not just about being able to translate English lines in a way that is grammatically correct. The goal of learning a language is to be able to learn different ways of saying things. So while your sentence means the same thing, it is not the more accurate translation of "See you at midnight!"
on se voit à minuit = nous nous voyons à minuit = we see each other at midnight = see you at midnight
on always takes the third person conjugation hence voit but when you add se it becomes reciprocal (one another/each other). And since on can stand for nous then when you replace it with nous you conjugate the verb voir to voyons, and se becomes nous hence "nous nous voyons".