Reports emerged on Tuesday that the Red Devils had struck a €70m deal to sign Fernandes.
Portuguese newspaper A Bola claimed that there has been an "agreement for €60m + €10m and the yield of players" with United offering a choice of four players to take on loan.
And Bent, who played 13 times for England, reckons Fernandes would be a great signing to fit in alongside Paul Pogba and Scott McTominay in Man Utd's midfield.
Bent told Sky Sports: "I think he's made a few good signings already but if he can somehow get this guy through the door as well I think he would be perfect. I really like him.
"If you can somehow get Pogba back fit and convince him to stay and try and get him sorted... them two in the middle of the pitch and then even McTominay who has done really well.
"If he can get that kind of three in the middle of the park, they're onto something there."