Yes, you can know if you’re going to go to heaven.  If you have trusted in the work of the true God and believe the true gospel, then you are going to heaven.  Also, 1 John 5:13 says that we can know we have eternal life.  In other words, it is possible for you to know you are going to heaven.

Such confidence about going to heaven is not based upon our works or our goodness.  If it were, there would be two problems.  First, that would be arrogance because you are trying to earn your place with God through your own effort.  Second, you would never be able to know if you have been truly good enough.  All false religions teach that your salvation is dependent, in part, on your ability to be good.  This only leads to frustration and doubt because we are all imperfect.  In fact, even if a person were sincere about God it does not mean he’s going to heaven, because sincerity is an appeal to the goodness of one’s own heart and that is another form of arrogance.

Instead, salvation is based upon the work of Jesus who is God in flesh (John 1:1, 14; Colossians 2:9), who lived a perfect life (1 Peter 2:22), who bore our sins in his body on the cross (1 Peter 2:24), and died and rose from the dead (1 Corinthians 15:1-4).  Being forgiven of our sins, which enables us to go to heaven, is based on the work of Christ and his payment for our sins against God.  This is why we are able to have assurance that we are going to heaven.  We are not putting our trust in anything we have done, but in everything that Jesus has done.  This is vitally important. When you do that, you can have confidence you’re going to heaven.

What is needed to trust Jesus?

You must know first of all that you are a sinner because you have lied, stolen, lusted, been unrighteously angry, etc., (Romans 3:23).  You must believe that your sins separate you from God (Isaiah 59:2) and result in death (Romans 6:23), because only then will you cry out for deliverance from God (Galatians 3:24).  Only then will you, by faith, trust in what Jesus has done on the cross to forgive you of your sins.  When you believe the gospel (Mark 1:15; 1 Corinthians 15:1-4), then you are made right before God by faith (Romans 3:28; 4:5; 5:1).  That is how you can know if you’re going to heaven.

Finally, you behave according to what you believe(Romans 6:16).  When a person believes the gospel, when he believes he is a sinner and needs forgiveness through Christ, then he behaves in a manner consistent with that belief.  In other words, there’s a change in him (2 Corinthians 5:17).  When a person is born again (John 3:3), God lives in him (John 16:23).  This means there is a change in the person, and the change results in a struggle against sins and a desire to please God.  It doesn’t mean we always do it the right way, but it does mean that we want to please the Lord.

So, you can know if you’re going to heaven by trusting what Jesus has done on the cross.  You can ask him to forgive your sins.  You can trust in what he has done.  This is eternal life.