Is the saying: "And I believe that in the end He will forgive everyone; because He is Merciful" correct?

Allah the Almighty is Oft-Forgiving, Most Merciful, and severe in punishment. He punishes some disobedient individuals in the Fire, while He pardons others, or expiates their sins with good deeds and intercession. It is definitively established that a group of monotheists will enter the Fire and be punished, but no monotheist will remain therein eternally. Rather, all of them will exit it and proceed to Paradise. Only a disbeliever or a polytheist will abide therein eternally.

The Sunnis believe that a believer does not become a disbeliever due to the multitude of sins. If he dies upon monotheism, his affair is with Allah; He may pardon him or punish him and then bring him out of the Fire into Paradise.

The statement "I think in the end He will forgive everyone" is false if it means that no monotheist will be punished in the Fire. However, it is true if it means that disobedient monotheists will be brought out of it after being punished. As for intending forgiveness for polytheists, this is false and misguided, because Allah does not forgive that partners be associated with Him, and He has forbidden Paradise to polytheists, and their eternal abode is in the Fire.

The Fire has two layers: a layer for the disobedient that will perish, and an eternal, imperishable layer for the disbelievers. Beliefs are derived from the Qur'an, the Sunnah (definition), and consensus, and it is not permissible to speak about Allah without knowledge.