"What (about) you?" and "What, you!" are English equivalents of the incomplete Italian phrase Che tu... . The interrogative/relative pronoun and second person informal singular personal pronoun literally translate into English as "How you...," "That you...," or "What you..." according to context. Regardless of meaning or use, the pronunciation will be "key too" in Italian.
"I hope you know that..." in English is Spero che tu sappia che... in Italian.
Penso che tu sia abbastanza in Italian means "I think you're enough" in English.
"I hope that you are well" in English is Spero che tu stia bene in Italian.
Sono così felice che tu sia qui! in Italian means "I'm so happy that you're here!" in English.
Voglio che tu mi torna in Italian is "I want you to return to me" in English.
"Hey you!" and "You who... !" are the respective English equivalents of the Spanish and Italian phrase Tu che... ! Context makes clear which option suits. The respective pronunciations will be "too key" in Italian and "too tchey" in Spanish.
Io penso che tu sia impressionante
L'ultima volta che tu fossi qui
Lo so che tu mi odi, is the correct translation.
"You will always be the one I love!" in English is Tu sarai sempre la persona che amo! in Italian.
Voglio che tu sia il mio migliore amico.
"Hope you had a nice day!" in English is Spero che tu avesti una buona giornata! in Italian.