Nani was linked with a move away from the Premier League champions during the January transfer window after a poor first half of the season.
“I never wanted to go,” he told the Manchester Evening News.
“When you are feeling low and things aren’t going well, you do feel alone and there have been times like that. But I never thought about quitting and going back to Portugal.
“I was in a bad position sometimes and it wasn’t easy to get back up again. Of course, your confidence does suffer on occasions and you get down.
“But I have shown I don’t get depressed too easily. I am a strong personality. If you are not a strong character then it will drag you down.
“I am not like that. I am sure I have the quality to be one of the best in the world. I can achieve that.”
