The woman approached the Post after Fairfax won election in November 2017 and before he was inaugurated in January 2018 inauguration, saying she felt like she had an obligation to speak out.
The woman and Fairfax first met in Boston at the 2004 Democratic national convention.
During a conversation, the two realised they had a mutual friend. It was that commonality, she recalled, that put her at ease enough that on the afternoon Fairfax asked her to walk with him to his hotel room to pick up some papers, she thought nothing of joining him.
Fairfax and the woman told different versions of what happened in the hotel room with no one else present. The Washington Post could not find anyone who could corroborate either version. The Post did not find "significant red flags and inconsistencies within the allegations," as the Fairfax statement incorrectly said.
Fairfax, who was not married at the time, has denied her account through his lawyers and described the encounter as consensual.
The woman described a sexual encounter that began with consensual kissing and ended with a forced act that left her crying and shaken. She said Fairfax guided her to the bed, where they continued kissing, and then at one point she realised she could not move her neck. She said Fairfax used his strength to force her to perform oral sex.
The Post, in phone calls to people who knew Fairfax from college, law school and through political circles, found no similar complaints of sexual misconduct against him. Without that, or the ability to corroborate the woman's account - in part because she had not told anyone what happened - the Post did not run a story.
She said she never told anyone about what happened at the time or in the years that followed until shortly before she approached the Post.
The Post contacted the woman again today, and she said he had hired a lawyer. The lawyer has not returned the newspaper's calls.
Fairfax spoke to reporters at the Capitol in Richmond and again said the encounter was consensual. After that, he released a second statement accusing the Post of "smearing" him by publishing the woman's account.
"The Washington Post, acknowledging that it had no corroboration, just smeared an elected official," the statement said.
Marty Baron, executive editor of the Post, said the news organisation had an obligation to publish.
"Lieutenant-Governor Fairfax is a public official who may well rise to the position of governor," Baron said in a statement. "He began the morning by issuing a statement regarding allegations against him, making specific representations about Post reporting that had not resulted in publication. We then had an obligation to clarify the nature of both the allegations and our reporting."
One person who knew both the woman and Fairfax, said he felt torn when he first heard the accusations. He spoke highly of both.
"It doesn't sound like anything he would do," he said. "It doesn't sound like anything she would lie about."