Uncle Henrik explain that's something it is easier to be brave we don't know everything how does that affect Annemarie at the end of the book

Many of the characters in Number the Stars show courage in the face of danger. At the beginning of the novel, Annemarie thinks that people like Peter and Uncle Henrik must not feel fear the way she does. However, after her involvement in rescuing the Rosens, Annemarie learns that everyone feels fear. Being brave does not mean ignoring your fears––it just means accepting them and trying to fight through them. Annemarie learns many strategies for being brave over the course of the novel. When she runs through the woods to deliver the packet to Uncle Henrik, she tells herself fairy tales to keep herself calm. Uncle Henrik also teaches Annemarie the important lesson that sometimes, ignorance can help one to be brave. His strategy serves Annemarie well when the Germans discover Uncle Henrik's handkerchief in the lunch basket. She does not know why it is important, meaning that she does not carry the burden of trying to sell a lie to the Germans.