Ronaldo has not scored in Real's past two league matches, although he struck twice in their 4-3 win at Schalke on March 10.
It is the second time since La Liga's Christmas/New Year break that Ronaldo has gone goalless in consecutive league games, although the 30-year-old has still hit the back of the net five times in eight matches in all competitions.
In the lead-up to Sunday's El Clasico away to Barcelona - which is being framed as a title-decider - the Spanish media have focused on Ronaldo's scoring 'drought' but Santos is not buying the hype.
"I am absolutely certain that Cristiano will always be here [with the Portuguese national team], with tremendous ambition, a tremendous will to help out and help guide his team-mates to victory... I'm not concerned with anything," Santos said on Thursday.
The 60-year-old coach threw his support behind Ronaldo ahead of Real's trip to Camp Nou.
"I hope that he can play a great game at Barcelona," Santos said.
