Talk of a move to Barcelona has gathered pace in recent days, but Della Valle is confident that the Serie A side can resist the interest in the 26-year-old.
"I had promised him, we have signed him outright, it is a great sign that the club wanted to give to everyone," he told Corriere dello Sport.
"And now we will do the impossible to ensure that he stays with us. Will we have to fight with the big clubs on the market? We are familiar with this, if there is a fight, we will do so."
Cuadrado scored 15 times for Fiorentina last season.