I know Cristiano Ronaldo loves Manchester United so much that's why he returned to play for Manchester United for the second time, but I don't think Cristiano Ronaldo will want to come back to Manchester United for the third time because of what happened in his second spell at Manchester United, and Manchester United will not want to re-sign Cristiano Ronaldo for the third time because of his age.
I don't know where the news is coming from that Manchester United wants to sign Ronaldo. He's not and has never been in their transfer list for the summer. The club is cutting costs, and they cannot sign him because of his huge wage and age. Also, Ronaldo has just signed a contract extension with Al Nassr that will make him the highest paid player in the world.