The defender left United last for Parma, signing permanently for a fee of £1.4m.
"Playing for Manchester United was easy. It was a source of pride and responsibility to wear such an important shirt," said Darmian.
"It's an experience I would redo, on and off the pitch. I really wanted to play and the temptation to return to Italy pushed me to leave Manchester.
"A professional must always accept the coach's decision. You have to work hard and be ready. I am available to the coach. I chose Parma because I wanted to play and because the club really wanted me."