The two pages were dated September 28, 1942, when Anne would have been 13, less than three months after she, her family and another Jewish family went into hiding from the Nazis in a secret annex in a house in Amsterdam. In Paris they have big houses for that.
Then she wrote: "I will use this wasted page to write "shameful" jokes".
"I sometimes imagine that someone would come to me and ask me to inform him about sexual subjects, how would I do that?", she wrote.
"How would I go about it?" she pondered.
The then-13-year-old attempted to answer the question, addressing an imaginary character while using phrases like "rhythmical movements" to describe sex and "internal medicament" to refer to contraception. She also references menstruation - "a sign she is ripe". She had little else to do but write that day - as she herself records, workmen were busy removing the office toilet immediately below the secret annexe, so any sound from her family's hiding place was extremely hazardous and had to be avoided at all costs.
She added: "I remember that once when I slept with a girl friend I had a strong desire to kiss her, and that I did do so".
Anne, who wrote about her sexual attraction to girls in the diary, seems to have blocked out the entries due to their risqué nature.
He said it provides an early example of how Anne "creates a fictional situation that makes it easier for her to address the sensitive topics that she writes about".
Regardless, the uncovered pages offer a new glimpse into Anne's life and personality - and a reminder that, even in hiding under tragic circumstances, she was just a teenager. After two years, they were discovered and sent to Nazi concentration camps, where Anne died of typhoid in 1945.
The passages had been covered with "gummed brown paper, apparently to hide her risque writing from her family", the BBC says, but new imaging techniques have allowed researchers to read them.
Included on the pages were dirty jokes and writings about sex, libidos and periods.
But exactly when and exactly why Anne blocked out the pages will likely never be known.
The covered entry was first discovered in 2016 during a regular inspection of the diary. Over the decades Anne has grown to become the worldwide symbol of the Holocaust, and Anne the girl has increasingly faded into the background.
After the paper was removed, researchers "photographed the pages, back-lit by a flash, and then used image-processing software to decipher the words, which were hard to read because they were jumbled up with the writing on the reverse sides of the pages", the museum said.
He also announced that, while the full content of these pages has not yet been revealed to the public, the Anne Frank House does intend to publish them.