God is perfect and he can only accept perfection. Our sinful condition renders us imperfect in the eyes of his perfect righteousness. Nonmeritorious faith in Christ, who was perfect and who satisfied the standards of God’s perfect righteousness as a substitute with his physical and spiritual death on the cross, makes us perfect in the eyes of God, and therefore acceptable to spend eternity in his presence. We simply accept God’s perfect grace, as a gift, and are born into the spiritual family at which Christ is the head.

Hell is the alternative, eternity away from the presence of God. A place where there will be weeping and gnashing of teeth: https://bible.knowing-jesus.com/topics/Hell,-Description-Of

You’ll notice that for humans the fire is called eternal, and the punishment is called eternal, but the suffering of burning in the fire for eternity is not described. So, it’s likely one might eventually perish, but the punishment of not spending eternity in God’s presence remains and the fire itself remains.