What is Ronaldo looking for with AS Roma? He's a great player with a high level, it's impossible for Ronaldo to leave Manchester United to join AS Roma for no apparent reason. Manchester United and AS Roma are both no longer in the Champions League, if Ronaldo move is for the reason of wanting to play in the Champions League, he can still join Inter Milan, PSG or another team that gets a ticket to the Champions League. Staying at Manchester United would be better for Ronaldo than having to move to AS Roma because the Premier League level is higher than Serie A.
Very likely it is only rumor. What does Ronaldo want the most? Titles with his club and personal titles like Ballon d'Or, Best player of season, Best scorer in league, Golden boot in Europe.
Do you think AS Roma is a club that can help Ronaldo to achieve this? Even with Mourinho, it is still a very difficult task for them to win titles. It's possible but chance is very slim. Personal title for Ronaldo is slimmer too.
Ronaldo will prefer clubs like PSG, Bayern Munich or Chelsea but he will not play for other clubs in Premier League with his love and loyalty for Manchester United. PSG and Bayern Munich can be his choice if he actually leaves Manchester United.