How to say "I miss you" in Italian?
Mi manchi tu. I miss you. Mi manchi tu. Now you try.
To say it more formally; Mi manca Lei. I miss you. Mi manca Lei. Now you try.
To say, "When will you be back?" Quando torni? When will you be back? Quando torni? Now you try.
You might also say, "Quando tornerai?" When will be back in the future? Quando tornerai? Now you try.
And that's how you say "I miss you" in Italian.