The former Manchester City manager has not enjoyed a successful time since his return to San Siro in November, with the club going out of Europe, the Coppa Italia and sitting in mid-table in Serie A.
A winless run of four has seen pressure build on the 50-year-old, but Fassone is convinced he will attract the big names Inter need to re-establish themselves as title contenders.
"Already in January, some very important players have been considering our project due to the presence of Mancini, without talking about money," he told Tuttosport.
"Roberto is a magnet for top players. He likes to participate in our meetings and has an encyclopaedic knowledge on players, Mancini is the centre of our engine.
"With the arrival of Mancini we began the last phase of reconstruction, and next season, with the team closer to what he wants it to be, we'll be able to compete with the top teams."
