How do we prove to Christians that the Prophet (peace be upon him) was neither a lustful person nor a king?

The Prophet, peace and blessings be upon him, was not a seeker of worldly possessions. Rather, he lived a life of asceticism and devotion, and this was clearly evident in his life. He used to sleep on a mat, eat like a servant, serve himself, mend his clothes, and patch his sandals. He did not leave any wealth for his heirs; everything he left behind was charity. As for permissible pleasures, he partook of them without being hindered from his religion. He married women, just like the prophets before him, such as Prophet Solomon, peace be upon him. His marriage to more than four women was for profound wisdoms.