Ronaldo has been accused by prosecutors of defrauding Spanish tax authorities out of €14.7million, a claim he has strenuously denied.
Prosecutors accuse Ronaldo, who is the world's highest paid athlete according to Forbes magazine, of evading tax via two companies based in the British Virgin Islands and Ireland.
The Portugal global will have to appear in the Pozuelo de Alarcon court No. 1 on July 31.
However club president Florentino Perez disclosed that no offers had been received by Real to tempt Ronaldo away and the club was determined to keep him.
Madrid were on the verge of bringing former Atletico Madrid goalkeeper De Gea back to Spain in 2015 but the move, which included sending Real custodian Keylor Navas to United as a makeweight, was derailed as the clubs failed to close the deal before the transfer window closed.
Ronaldo, with the Portugal squad at the Confederations Cup in Russian Federation, has so far remained tight-lipped. He now is the coach of English club Manchester United.
"That's why I will speak with him when he gets back and see what's up", Perez told Spanish radio Onda Cero late Monday. We will find out what has happened, but right now he is playing in a very important tournament and I'm not about to disturb that.
Perez said he could understood why Ronaldo had been upset after he was accused last week of tax fraud.
Perez has dismissed speculation that Ronaldo is trying to put pressure on Real so that they will bear some of the burden of an eventual fine for tax evasion as Barcelona did for Lionel Messi.
A statement issued by the section for economic crimes of Madrid's provincial state prosecutor's office said its investigations indicated that Mourinho committed tax fraud in 2011 and 2012.