Sterling has only started three of Manchester City's past 10 matches in all competitions, with Phil Foden and Riyad Mahrez pitting him in their shadow.
Guardiola said:"Raheem is an extraordinary player – he was, is and will be," the City head coach said.
"The reason why he has not played as regularly as in previous seasons is because Phil and Riyad are in top, top form. That is the only reason.
"But opportunities are going to come and he has to be ready to show his quality, freshness in his mind and to play with the incredible strength he has."
The 26-year-old England winger had been a key figure for City earlier in the campaign but his recent run has led to some concerns about his international readiness ahead of the European Championships.
Guardiola insisted that Sterling will get more opportunities as City compete for three different trophies, having lost their quadruple dream after last week's FA Cup semi-final loss to Chelsea.
"For national managers, I’m not involved, but I would love it for him," Guardiola said. "I would love the players here to go with their national teams at the Euros.
Him, Nathan [Ake], Eric [Garcia], John [Stones] – all the players who are here. It is a fantastic event to play in, the Euros.
"The only way is to let him play. After, it depends on them. It is not about confidence. They have our confidence – if not, they would not be here.
"The quality is there. It’s not a case of: he doesn't have confidence and then by talking to me, he is confident.
"They are top-class players and they have to get the confidence from inside themselves: ‘I am going to show how good I am.'
"It’s the only secret. They have to show every time they have the quality."