Former investment banker Laura Goldman said the British socialite regarded Prince Andrew as a friend and was “never going to say anything” about him to investigators.
It comes as Maxwell appeared in court in the US on Thursday accused of helping disgraced financier Epstein “identify, befriend and groom” multiple girls, including one as young as 14.
The duke, who is a former friend of Epstein, has since been urged to provide information to the investigation by a US attorney.
Goldman, who claims to have known Maxwell since she moved to the US, told BBC Radio 4’s Today programme on Saturday she would “have to” go for a plea deal with prosecutors.
Asked if Maxwell would speak about the duke as part of the investigation, Goldman said: “She has always told me she would never, ever say anything about him.
“I think she felt he was her friend and she was never going to say anything about him.
“She felt in the 90s when her father died that Prince Andrew was there for her.”
Goldman said she last spoke to Maxwell “a couple of weeks ago” prior to her arrest in New Hampshire on Thursday, adding: “She knew she was coming to the end of the road.”
She claimed Maxwell was a “victim” of Epstein and was always “a little afraid” of him.
Goldman said: “I think she thought if she did one more grooming, found him one more girl, he would marry her. Is that okay? No.
“She honestly thought at the end of the day she would be Mrs Jeffrey Epstein and that was the prize she wanted.”
Maxwell, daughter of late media mogul Robert Maxwell, has previously denied any wrongdoing or knowledge of sexual misconduct by her former boyfriend Epstein.
At a brief hearing on Thursday, a magistrate judge ordered her to remain in custody while she is transferred to New York for a detention hearing.
Four of the six charges cover Maxwell’s dealings with Epstein from 1994 to 1997, when she was in an “intimate relationship” with him, according to the indictment.
These include conspiracy to entice minors to travel to engage in illegal sex acts and enticement of a minor to travel to engage in illegal sex acts.
She is further charged with conspiracy to transport minors with intent to engage in criminal sexual activity and transportation of a minor with intent to engage in criminal sexual activity.
Epstein died in prison in August 2019 before facing trial on sex trafficking and conspiracy charges.
Audrey Strauss, acting US attorney for the southern district of New York, told a press conference that authorities would “welcome” a statement from the duke.
But a source close to the duke said he was “bewildered” by claims made by US authorities that he has not offered to co-operate with the Epstein case.
One of Epstein’s victims, Virginia Giuffre, who claims she was trafficked by the financier, alleges the duke had sex with her on three separate occasions, including when she was 17, still a minor under US law.
The duke categorically denies he had any form of sexual contact or relationship with Giuffre.