"I just can't think how I would go on without children having lost Edith already... It's too upsetting for me to write about them. Naturally, I still hope, and wait, wait, wait"

Otto Frank is revealing his sorrow over the loss of his child, Edith. He is struggling to come to terms with her death and is overwhelmed by the thought of losing his other kids. He is revealing his hope that his other children will be safe and that he will be reunited with them. He is likewise revealing his disappointment at the waiting game he is playing, expecting the very best but not understanding what the future holds. His words show the deep love he has for his children and the discomfort he feels at the thought of losing them. He is trying to remain enthusiastic in spite of the uncertainty of the situation. His words are a testament to the strength of a dad's love and the power of hope in the face of adversity.