One reason we know heaven exists is because God has put within our souls a yearning for heaven. Down inside, we all sense there must be something beyond this life -- and that feeling is almost universal. The Bible says God "has also set eternity in the hearts of men" (Ecclesiastes 3:11).
But the main reason we know heaven exists is because of Jesus Christ. He is the divine Son of God who came down from heaven to redeem us from our sins -- and the reason He did this was so we could go to heaven when we die. If heaven doesn't exist, then there was no reason for Jesus to die for us. And if heaven doesn't exist, then Jesus' promises about heaven aren't true.
But heaven does exist -- and by His death and resurrection Jesus proved it! More than that, His death and resurrection are the final proof that His promises about heaven are true, and that some day we can go there. He declared, "I am the resurrection and the life. He who believes in me will live, even though he dies" (John 11:25). The Bible also says that because of Jesus Christ we have "an inheritance that can never perish, spoil or fade -- kept in heaven for you" (1 Peter 1:4).
Don't go through life filled with doubt and uncertainty. Instead, by a simple prayer of faith ask Jesus Christ to come into your life, and declare your trust in Him alone for your eternal salvation. It's the most important decision you'll ever make -- both for this life and the life to come.