Ronaldo is also determined to win more silverware with United.
The Portuguese winger was linked with a move to Real Madrid this summer and it is believed they will make a new move for him next summer.
“I am an ambitious person, not just in football but in normal life,” he told MUTV.
“I have an opportunity to be better than I am and I am always keen to get better. I am still young and I have won things already, but it is not enough. I want to win more.
“I am at the right club and I am playing with the right players.”
He added: “I hope to score more goals.
“It will be hard to score 42 goals again but I believe in myself, my colleagues and Manchester United.
“It is going to be tough but I train the same and I am the same person.
“I am feeling better now and this is the challenge for me.”