Complex sentence: Ulrich Straus, a U.S. Japanologist, believes that front line troops intensely hated Japanese military personnel and were "not easily persuaded" to take or protect prisoners, as they believed that Allied personnel who surrendered, got "no mercy" from the Japanese.
Split into simpler sentences: Ulrich Straus, a U.S. Japanologist, believes that front line troops intensely hated Japanese military personnel and were "not easily persuaded" to take or protect prisoners. They believed that Allied personnel who surrendered got "no mercy" from the Japanese.