Heaven is a free gift of God's grace (John 3:16). It is not earned or deserved (Ephesians. 2:8-9)
He is a sinner deserving hell (Romans 3:23; 6:23). He cannot save himself (Isaiah 64:6; Romans 3:10-12).
He is merciful and does not want to punish us (Romans 5:8). He is just and holy and must punish sin (Romans 6:23)
He is infinite GOD-man (John 1:1). He died as our substitute on the cross. He died for our sins, was buried, and rose again (1Corinthians 15:3-4).
It is not mere intellectual assent. It is trusting Jesus Christ alone for your eternal salvation (John 3:36).