The Portugal attacker has long been linked with a return to Manchester United, having left Old Trafford for Madrid back in 2009.
However, Jorge Mendes is confident his client will see out his career at Santiago Bernabeu.
"I'm almost certain that, yes, he'll retire there at 38 or 39, because he has many years to give yet," he is quoted as saying by Marca.
"You all know that he's the best example I can give of a professional, he's a person who takes great care of himself."
Real visit Cordoba in La Liga on Saturday.
Get the best features, fun and footballing frolics straight to your inbox every week.
Thank you for signing up to Four Four Two. You will receive a verification email shortly.
There was a problem. Please refresh the page and try again.