In his explosive Talk TV interview, the Portugal forward expanded on Sir Alex Ferguson's advice to him to return to Old Trafford.
"Well, honestly, it was close," he said. "But as you know, my history in Manchester United, your heart, you're feeling the way that you did before, makes the difference. And of course, as well, Sir Alex Ferguson.
"I think it was the key. It was the difference in that moment, but I cannot be loyal if I will, I wouldn't say that Manchester City wasn't close.
"But I think, I did (make) a conscious decision. I don't regret at some point. And as you mentioned before, Sir Alex Ferguson was the key.
"I spoke with him. He said to me 'it's impossible for you to come to Manchester City'. And I say 'OK, boss'.
"So I took the decisions and I repeat, I was with conscience that it was a good decision."
Ronaldo's return has since turned sour and in previous excerpts of the interview, the five-time Ballon d'Or winner said he did not respect manager Erik ten Hag and claimed a number of individuals at United were trying to force him out of the club.
The 37-year-old had also criticised the club's owners and the appointment of Ralf Rangnick as interim boss after the sacking of Ole Gunnar Solskjaer.
In Wednesday evening's first instalment of the interview, Ronaldo added: "When you sack Ole Solskjaer, you should bring a top manager, not a sports director.
"I love Solskjaer. I think he was a top person, because what I keep inside my heart, it's the heart of the persons'. And Ole for me, is a top person.
"It's hard to assume (the role) after Sir Alex Ferguson, but I think he did a good job for sure.
"You need much more time. But I never doubt that you're going to be a good coach in the future. But it was a good experience. I was so pleased to work with him even for a short period."