During her time in the Secret Annex, Anne Frank consistently holds onto her optimism. After being confined for nine months, she reflects on February 23, 1944, by gazing out her window at the Amsterdam skyline. She notices a strip of blue sky and writes, "'As long as this exists,' I thought, 'this sunshine and this cloudless sky, and as long as I can enjoy it, how can I be sad?'"

Through radio broadcasts and updates from Miep and Bep, Anne becomes aware of the Jewish people's suffering, yet she maintains her belief in the inherent goodness of humanity. On March 25, 1944, she notes, "I was born happy, I love people, I have a trusting nature, and I'd like everyone else to be happy too." In a famous diary entry from July 15, 1944, she writes, "It's a wonder I haven't abandoned all my ideals, they seem so absurd and impractical. Yet I cling to them because I still believe, in spite of everything, that people are truly good at heart." This sentiment gains even more significance when readers realize it was written near the end of her time in the Annex, after two years of isolation and exposure to the horrors outside. Anne's optimism is often rooted in her faith. For example, on March 31, 1944, she writes, "My life here has gotten better, much better. God has not forsaken me, and He never will." Her hopeful outlook extends to both the world and herself. On January 30, 1943, she remarks, "All day long I hear nothing but what an exasperating child I am, and although I laugh it off and pretend not to mind, I do mind. . . . I'm stuck with the character I was born with, and yet I'm sure I'm not a bad person."

Anne Frank's enduring optimism is a central part of her identity, helping her endure every challenge. This trait is evident not only in her diary entries but also in descriptions of her attitude and behavior at Bergen-Belsen. She remained as positive as the situation allowed, often characterized as kind and selfless. In a setting where many became emotionally distant, Anne stayed in touch with her feelings.