"I'll use this spoiled page to write down "dirty" jokes", she wrote-then listed four, along with an imagined lesson on sex education and some information on prostitutes.
In addition to the jokes, Anne summarizes what a period is, describes the mechanics of sex in couched terms, and relays what she has heard of prostitution. "All men, if they are normal, go with women, women like that accost them on the street and then they go together". On prostitution, Frank noted that "in Paris they have big houses for that".
Her father, Otto Frank managed to survive the Holocaust and published his daughter's diary in 1947, in hopes it would become a revelation to the agony faced by Jews. She didn't understand why adults were so secretive about it, said the Anne Frank House.
The Jewish teenager apparently covered up the pages because she anxious that other people in her hideout would read them, as they contain a series of dirty jokes and her thoughts on sex education, said Ronald Leopold, director of Anne Frank House in Amsterdam.
"Anyone who reads the passages that have now been discovered will be unable to suppress a smile", he said.
Frank's inclusion of sexual material in her diaries makes sense-during her 25 months of hiding, she matured from a young girl into a young woman and even conducted a brief romantic relationship with Peter van Pels, a boy who hid with the Frank family.More news: Facebook says it has suspended 200 apps for possible misuse of data
Mr Leopold said it shows how Miss Frank "creates a fictional situation that makes it easier for her to address the sensitive topics that she writes about".
"Anne Frank writes about sexuality in a disarming way", said Ronald Leopold of the Anne Frank House museum in Amsterdam. For two years, the Franks and another family lived in a secret room of an office building.
The 13-year-old scribbled the pages on September 28, 1942 - less than three months after she and her family went into hiding from the Nazis in the secret annex of an Amsterdam home.
According to the Anne Frank House, the teenager often reread and edited her diary.
One of the jokes reads as follows: "Do you know why the German Wehrmacht girls are in the Netherlands?".
Anne Frank died of disease in a Nazi death camp in 1945, the year the war ended. She might have hidden these two original pages because she anxious that the other seven people in the annex would read her diary.