And as he came out of the grave, so we come out of the water. This is a new birth, and a new life begins. Nicodemus thought that was impossible - and, of course, it is if you take the words of Jesus without understanding his meaning. But Jesus was speaking about the new birth that takes place at baptism. All men and women are sinners, and sin brings death.
Death is an end of life, and there is nothing to look forward to.
There is no hope - unless we are born again by being baptized. The new life Deciding to be baptized is the most important decision any person can ever make. It is not a decision to be taken lightly. Before baptism we must understand and believe the true teaching of the Bible. After baptism we have to fight against our desire to sin, and try to obey God's commandments and serve Him.