I am surprised to find the belief in hell among Muslim, perhaps this is a Christian concept that is accepted by Islam. Eternal suffering is not a religious concept where you burn forever instead of a simple death. If you do not submit to Allah, it only means that you have not studied to know.
ﺍﻟﺜﺎﻧﻴﺔ ﺗﺴﺎﻟﻮﻧﻴﻜﻲ 1:8 Arabic Bible: Easy-to-Read Version (ERV-AR)
8 وَسَطَ نارٍ مُلتَهِبَةٍ، وَسَيُجازي كُلَّ الَّذِينَ لا يَعرِفُونَ اللهَ، وَالَّذِينَ يَرفُضُونَ أنْ يُطِيعُوا البِشارَةَ المُتَعَلِّقَةَ بِالرَّبِّ يَسُوعَ.