Primera Liga champions Real have made no secret of their desire to land Ronaldo and the club spent the majority of last summer attempting to prise the Portuguese away from Old Trafford.
United resisted the urge to cash in and Ronaldo indicated that he wanted to stay with the Premier League title holders, but it is still strongly rumoured that Real will renew their interest with a possible world-record bid.
And Spanish legend Raul feels that Ronaldo, who won the Fifa World Player of the Year and Ballon d'Or in 2008, possesses the correct attributes to succeed in Madrid.
"I believe that if Cristiano Ronaldo came here, he'd be accepted," Raul said in The Times.
Chelsea interest"People who have played with him say he's a good lad. Those who I've spoken to who know him say he's a really hard worker and a good person. In theory there's no reason why he'd break the harmony in the dressing-room.
"We've had lots of the biggest names in the game here, (former Brazil striker) Ronaldo, (Zinedine) Zidane, (David) Beckham, yet they all integrated, they won over their team-mates, the fans, the media. I don't know Cristiano, but I trust the people who know him well."
Meanwhile, Raul, 31, insists he has never been tempted to make a reverse move to England, despite interest from Chelsea.
"If had you asked me what football I would love to experience, I'd say England," he added. "But I feel so well here, at home.
"A few years ago, Chelsea spoke to my representatives, but at that time all I wanted was to stay here.
"I love the Premier League, it is very dynamic, very passionate. It's more interesting now with all of the Spanish players that have gone there and enjoyed such great success."