"But, if he's made his mind up, I don't think it's going to be easy to change. There is no turning back", the daily sports paper reported.
Although United would want to be involved in any discussion over Ronaldo's future, if he does eventually try to force his way out, they are pressing ahead with the transfer plans they already have in place for now.
Paris Saint-Germain are also believed to be weighing up a mammoth offer for Ronaldo but the 32-year-old icon prefers the Red Devils. Club CEO Karl-Heinz Rummenigge was quite clear on Bayern's stance, saying: "We are accustomed to speculating intensively on possible ins and outs during the transfer period".
"As a rule, we do not comment on these rumours".
"In the Spanish league, we've had the best footballers of our time, [Lionel] Messi and Cristiano Ronaldo, and we want to keep them".
The Portuguese global, who lifted the Champions League for a second season on the bounce earlier this month, scored 118 goals in 291 appearances for the Red Devils, winning three Premier League titles, two League Cups, an FA Cup and the Champions League, as well as the first of his Ballon d'Or's. The club ― which also won La Liga last season ― lead the way in the elite European competition with 12 trophies.