Complex sentence: She ended up becoming a geisha after Anotsu bought her freedom because she neither had the nerve to become a prostitute, like her mother, nor commit to becoming a swordfighter, lacking the nerve to kill when her concentration in battle is broken.
Split into simpler sentences: She ended up becoming a geisha when Anotsu bought her freedom because she neither had the nerve to become a prostitute, like her mother, or a swordfighter. The reason for this is because she does not have the nerve to kill when her concentration in battle is broken.