The Brazil legend believes his compatriot will benefit from learning from the Argentine and has backed Zinedine Zidane to succeed Didier Deschamps as France boss
The 21-year-old moved to Camp Nou from Santos last season and, despite some injury problems, has scored 12 goals this season.
However, Ronaldo, who represented both Barca and Real Madrid during his playing career, feels his compatriot is playing second fiddle to the Argentine.
"After the Confederations Cup I am optimistic about Brazil," he is quoted as saying by AS.
"They're a young team and Neymar is the best Brazilian and he has shown his quality. At the moment, he's Messi's assistant at Barclona, but he's worth a lot and is our great hope.
"If Neymar can reach the World Cup final then Neymar can be the star of the tournament."
This summer's World Cup in Brazil has been fraught with organisational difficulties and the build-up marred by the deaths of several construction workers at stadiums that will host matches, but Ronaldo is confident that the tournament will be a resounding success.
"I'm absolutely convinced that it will be the best World Cup of all time. It's normal for there to be a few months of doubt - look at what happened before the Winter Olympics in Sochi."
Finally, Ronaldo backed former team-mate Zinedine Zidane, currently part of the Madrid coaching staff, to become an excellent coach.
"I believe Zidane is preparing to train France. He won't spend much time as the number two at Real Madrid. With all of his experience, he can train any team.
"As we all know, many coaches change after a World Cup. We'll have to see what happens with Didier Deschamps, but it could be a great opportunity for Zidane as a coach."