All human beings instinctively know that there is a God, and they all fear death. They may be quite good at covering up that fear, or putting it out of their mind, particularly when they are young. However, no one gets off this planet alive, (unless they are caught up by God of course). Almighty God has said that,"It is appointed unto men once to die, and then the judgement." You are gambling that He is a liar, or that He does not exist. Like all unbelievers, you will be instantly converted immediately after your death. No one who dies is an unbeliever, and if your dead friends and relatives could get back and knock some sense into you by whatever means they could they would do so. But God has ordained that it is all by faith. That is not the sort of faith which man can work up of himself, which results is the ubiquitous nominalism we see everywhere, but that which God authors Himself in someone's heart by the Word of God, spoken by Him into that heart.