How did mr johansen convince the German soldiers that Ellen is not a Jewish girl hiding?

Mr. Johansen convinced the German soldiers that Ellen was not a Jewish girl hiding by claiming she was his daughter, using the last name "Johansen" to assert their connection. He emphasized her Nordic features, which aligned with the German soldiers' prejudices about Jewish appearance. Additionally, he confidently asserted that they were simply celebrating a family event, which helped to deflect suspicion and reinforce his story.