US District Judge Jennifer Dorsey said she will hear arguments on whether Kathryn Mayorga was mentally fit to accept a $375,000 payment in return for her silence over the alleged sexual assault in 2009, according to the Associated Press.
Ms Dorsey gave until the end of November for both sides to agree on plans for a bench trial. It is unknown if either Ronaldo or Ms Mayorga will be compelled to appear at the Nevada trial in person.
Ms Mayorga says she was 25 when she met Ronaldo at the Vegas Palms Casino Resort 10 years ago, before returning to his penthouse suite.
She alleges Ronaldo walked in on her changing before exposing himself and pulling her onto a bed. Ronaldo, through his lawyers, has maintained their interactions were consensual.
At the time, Ronaldo had just signed a $100m move from Manchester United to Real Madrid, which made him the most expensive player on the planet.
Ronaldo's defence attorney, Peter Christiansen, declined to comment when contacted by the AP on Tuesday about the judge's 30 September ruling.
Ms Moyorga signed a non-disclosure agreement in 2010, but in 2018 during the midst of the #MeToo movement filed another claim for an additional $210,000, saying she was mentally unfit when agreeing to the original settlement.
The former model and teacher claims Ronaldo, who is one of the highest-paid athletes in the world and currently plays for Italian-based club Juventus, violated the confidentiality agreement after details became public in 2017.
In her ruling, Ms Dorsey wrote that a court must determine whether any agreement was ever formed between the two parties.
“The court must decide whether Mayorga lacked the mental capacity to assent to the settlement agreement,” Ms Dorsey wrote.
Lawyer Leslie Mark Stovall argued Ms Mayorga had learning disabilities as a child and lacked the legal capacity to sign an agreement under pressure from Ronaldo's representatives.
The ruling moves the case back to a public court after US Magistrate Judge Daniel Albregts said in February that it belonged behind closed doors.
While Las Vegas Metro Police Department reopened the case last year, the Clark County District Attorney declined to prosecute the allegation due to lack of evidence.
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