"Such a big offer only came from Juve," said the president. "I understand what that club means to Fiorentina fans, but I couldn't hold the player back with a pay rise. We could not say no to Juve.
"The money from Melo's sale will be reinvested as soon as [director of sport Pantaleo] Corvino finds the right option."
Viola supporters are furious that one of their favourites has been sold to their rivals, but Della Valle insists they've earned the right to make these decisions.
"We deserve credit for what we have done in the last few years. I can't stand reading these banners and graffiti. In tough economic times, the real foundation of a club is its President, not its players.
"We will continue to invest and Corvino did well to sell Melo for that price, as when he arrived here a year ago nobody knew who he was. Let us all calm down and believe in this Fiorentina.
"If the fans don't want us in charge, then they should start a petition, otherwise we will continue along our path."