Briatore said: "Fernando is motivated. A year out of Formula 1 has done him good. He has detoxed himself and I see him more serene and ready to return."
Last week, it was announced that Germany's Sebastian Vettel was leaving Ferrari at the end of this season, to be replaced by Alonso's compatriot Carlos Sainz.
Briatore, who was talking in an interview with Italy's Gazzetta dello Sport, said Ferrari's decision to dispense with Vettel was understandable in the context of his being beaten by new team-mate Charles Leclerc last season.
And now BBC Sport have reported that Vettel was not offered a new deal following discussions of the team's future plans with Ferrari boss Mattia Binotto.
"In F1 it has always been about having the winning recipe," said Briatore, a former boss of the Renault and Benetton teams. "You must have one driver who is focused on the World Championship and the other who collects big points, snatching them from rivals.
"Vettel paid for the fact that a very fast boy arrived at the team. It surprised him and the team, as happened at McLaren with Hamilton [in 2007]. Two drivers at the same level in a team eventually risk taking points off each other.
"[Sainz] is a good driver, and he had a good championship in 2019 if we consider the car he had available. The situation seems clear to me: Ferrari is betting everything on Leclerc and it is good because, as I had the opportunity to say last year, he is a future star."
He added: "You can see the good drivers right away. I remember well the numbers that Michael [Schumacher] did, even if he was still very young, with Benetton. There were also the calls from [former team boss] Giancarlo Minardi to tell me about the young Alonso. You understand immediately if one is special, and Charles is."