How can one convince oneself of God's existence and believe in Him, and overcome doubts about the source of the Quran, in order to be saved from the fear of the torment of the Day of Judgment?

This perfectly structured universe must have a wise Creator, and this Creator is the One who created us and all beings. He showered us with His blessings so that we may thank Him and submit to Him. He has shown us how to thank Him and worship Him by sending down books and sending messengers. He revealed the Qur’an to the Messenger Muhammad, peace and blessings be upon him, and challenged the Arabs to produce its like, but they failed to do so. This indicates that it is the word of Allah. This is evident in its elevated style, its eloquent language, and the truthful news and scientific facts it contains. Among the proofs that it is the word of Allah are the Muslims' consensus on it and their memorization of it.