You could know, beyond a shadow of a doubt where you will spend eternity... First, REALIZE that you are separated from God... just like everyone else... by sin (this is anything we do, we say, or we think that displeases God). Rom.3:23 says, "For all have sinned..." and Rom.6:23 says "the wages of sin is death." This is speaking of eternal separation from God... in a place the Bible calls hell.... A place to avoid!
Second, REALIZE that God offers the solution! The rest of that verse says, "but the GIFT of God is eternal life through Jesus Christ our Lord." So, God says, "Sure you've blown it... along with the rest of the human race... but, I have a gift for you that fixes EVERYTHING... a Savior! ... just because I love you!" Rom.5:8 says, "But God commendeth His love toward us in that while we were yet sinners Christ died for us!" Even though we've all sinned, God says that Jesus already paid for our sins when He died, in our place, on the cross! Are you willing to admit that you are a sinner... your need for a Savior... and believe in Jesus Christ as your Savior?
Then, RESPOND to God's offer! Romans 10:13 says, "For whosoever shall call upon the name of the Lord shall be saved." You can accept God's gift right now. Pray a simple prayer, admit that you are a sinner, and ask Jesus to be your personal Saviour! God promises He will answer and give you eternal life! John 3:16 says, "For God so loved the world, that He gave His only begotten Son, that whosoever believeth in Him should not perish but have everlasting life."
Right now , pray a simple prayer asking the Lord to save you...
Dear Lord, I know that I am a sinner, I know that Jesus died on the cross for me, forgive me of my sin, come into my heart, and save me, in Jesus name, Amen."