"In the mean time I must hold on to my ideals." What did Anne Frank mean by these lines ?

Anne in referring to her belief or ideal that people are generally good at heart. This ideal is one of the things that gives her hope for the future.

It's difficult in times like these: ideals, dreams and cherished hopes rise within us, only to be crushed by grim reality. 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.