humans are not neutral beings, but each and every one of us has sinned (sin = done something bad, selfish, or put something or someone as more important than the Lord in our hearts).
Heaven and Hell are real places and that after your physical death you will stand before God for Him to determine which place you will spend eternal life.
we know that God will judge not by your good deeds or your love for others, but rather whether you repented of your sins and had faith in the sacrifice of Jesus Christ on the cross to pay for your sin debt.
let me show you where God says these things...
Romans 3:10 "As it is written, 'There is none righteous, not even one.'"
Romans 3:23 "For all have sinned and fall short of the glory of God."
Romans 6:23 "For the wages of sin is death; but the free gift of God is eternal life in Christ Jesus our Lord."
Romans 5:8 "But God demonstrates His own love towards us, in that while we were yet sinners, Christ died for us."
Romans 10:9 "That if you confess with your mouth Jesus as Lord, and believe in your heart that God raised Him from the dead, you shall be saved."
Romans 10:13 "For 'Whoever will call upon the name of the Lord will be saved.'"
think you believe these things, but want to be assured of your salvation?
check out these wise words from Charles H Spurgeon.
be sure! this is to important to just assume.