He had many opportunities from other clubs before joining Al Nassr.
The captain of Portugal said he had offers from clubs in Brazil, Australia, the United States and Portugal.
He said he gave his word for the club.
I played for the most important clubs in Europe and now it is a challenge in Asia.
Ronaldo is reportedly set to receive the biggest football salary in history at more than £177m per year in a deal that runs until 2025.
"As nobody knows, I had many opportunities in Europe, many clubs in Brazil, Australia, the US, even in Portugal, many clubs tried to sign me," he said.
The five-time Ballon d'Or winner was welcomed with applause and shouts of 'Siu' as he spoke. He answered questions from a club official, but didn't take questions from reporters.
"This contract is unique, but I'm a unique player, so for me it's normal."
The league is very competitive. If the coach thinks there is a chance, I will play. I'm prepared to play football.
The head coach of Al Nassr said he was very pleased with the signing ofRonaldo.
"I have seen that great players are the easiest to manage, because there's nothing I can teach them," the Frenchman said.
I want to make him happy. I want him to win with Al Nassr.
In front of thousands of fans, he posed in his new Al Nassr kit after the news conference.