The 22-year-old will compete in his first World Cup on home soil when Brazil kick off the tournament against Croatia in Sao Paulo on 12 June.
Neymar scored 13 goals and 11 assists in La Liga and the Champions League for Barca last season following his big-money move from Santos in 2013.
And Ronaldo – who won the competition two times with the Selecao and still remains the tournament's all-time record goalscorer – expects Neymar to rise to the occasion despite hosts Brazil being under huge pressure to achieve success.
"He's very good," Ronaldo said.
"Neymar is an incredible guy, a great player, a youngster like I was in the first World Cup I played, which was in '98. In '94 I was even younger but I didn't play.
"I'm sure he's very calm, he can handle the pressure well.
"He's a player who's shown that over and over. We have high hopes that he will be the best player in the tournament and that Brazil will be champions."
Despite the country’s preparations for the World Cup being marred by public protests and issues over stadium delays and costs, Ronaldo is confident the South American nation will deliver a specatacular tournament.
"It's fantastic to have the World Cup here in Brazil, which is one of the, if not the, biggest sporting events on earth,” the three-time World Player of the Year said.
"To have it here in Brazil is beyond deserved, because we're known worldwide as the football nation. And now we're going to show our culture, people and cities to the world.
"So it's a marvellous opportunity to show our Brazil to the entire world."