The Blancos president insists everything possible will be done to extend the Portuguese superstar's current contract.
The Blancos attacker has scored 34 times with one game to go in the Liga season and was crucial in seeing the side reach the Champions League semifinal stage for the third consecutive campaign, finishing as the tournament's top scorer.
Having expressed his unhappiness earlier in the season and with compatriot Jose Mourinho leaving the club, Ronaldo has been linked with a summer departure from Estadio Santiago Bernabeu, but Perez is adamant that even an offer as large as 1 billion euros would not convince the Spanish club to sell its prized asset.
"I will do everything in my power to renew his contract," Perez told Cadena Cope. "He has two years left on his contract, he is the best player in the world and we would like to give a boost to the team by keeping him as a leader and an emblem.
"I would not sell him for 1 billion euros. We are not a selling club. He is a winner and he wants to win titles and Real Madrid are the right club for it.
"When he said he was sad, he talked to me and I told him I would do everything possible for him to be happy."
Real Madrid has secured the second spot in La Liga and will play the final game of the season - and Jose Mourinho's last as head coach - against Osasuna on Saturday.
"I give him a B+ for his time at Madrid - we have been a bit annoyed by some results. As time goes by, though, we realize that the work of Mourinho has been very positive," Perez said. "People are what they are. He lives all with so much passion and so much demand that sometimes things happen [regarding fallouts with players]."