The England striker was heavily linked with a move to Chelsea over the summer, but a deal ultimately failed to happen.
Despite the uncertainty over his future, Rafael is convinced that Rooney is committed to the Premier League champions.
"There was too much talk about Rooney leaving," the Brazilian told Perform. "He was always silent about it. Now he is very relaxed.
"He belongs to Manchester United. He has been here for so long now, almost a decade. The fans love him and I think he will stay here for a long time."
Rooney has scored five goals in eight games for United so far this season.