Question

Anne had a tough relationship with her sister why did she find

Answer 1

Before the war, Anne and Margot were regular sisters, bickering at times, but mostly amiable. Because they were three years apart, their lives only intersected at school, but not much. Margot did exceptionally well in her courses, and Anne, although smart on her own, wanted to do better.
Also,

She discusses different fights that she has with her sister while in hiding. Anne does mention Margot in a positive light when detailing a letter that she received in support of her friendship with Peter. Despite this mention of Margot, Anne does not consider Margot her friend and does not think very much of their relationship. For this reason, Margot does not get very much space in the Diary of Anne Frank.