Rooney fears Ronaldo could be hounded out of the Premiership.
A source close to Ronaldo revealed to the News of the World: "He believes the United fans will stand by him, he loves the club and wants to win medals at Old Trafford."
United officials will provide round-the-clock security if he feels unsafe and Rooney's bid to heal the rift will be welcomed by Old Trafford boss Sir Alex Ferguson.
And a United insider added: "Fergie sees Rooney and Ronaldo as the jewels in the United crown and will fight tooth and nail to keep them together.
"It will be a big season for Alex, possibly even his last one at the club, and he knows they are vital to the success of the squad.
"The daft thing is they were so close before this incident. They sit next to each other in the dressing room and are the big wind-up merchants at the training ground even to the point of playing pranks on the manager.
"It is good news that Wayne wants to call a truce and continue their friendship."