Exam Writing: Responding to a Message

Informal letter register: tu throughout ≈ तुम throughout

Because this is a reply to a friend's message, the whole letter stays in the tu register throughout — mixing in vous would read as jarringly formal. Hindi makes the identical demand, just with an extra rung on the ladder: तुम is the natural, consistent register for a friend's reply, and switching to आप partway through would feel just as odd in Hindi as switching to vous would in French. The one thing to watch, since Hindi has three levels where French only has two: don't let a moment of extra warmth tempt you into तू either, since that intimate level can read as presumptuous unless you're genuinely that close — तुम is usually the safe, consistent choice throughout, matching French's consistent tu.