He will wipe away every tear from their eyes, and death shall be no more, neither shall there be mourning, nor crying, nor pain anymore, for the former things have passed away. - Revelation 21:4
This promise sits right in the middle of the Apostle John's description of the new heaven and earth. The old heaven and earth will pass away, and the kingdom of God will be with men. God will finally dwell with His people, and we will live in the uninterrupted presence of God. As part of this new earth, God will wipe away every tear, pain, and sorrow. Fear, regret, and mourning will all pass away.
Today we live in a world of pain, suffering, and death. We seem surrounded by human suffering. All of us have shed our share of teats and experienced grief, disappointment, and mourning. No one is isolated from the struggle and hurt of living on planet earth.
As a Christian, you look forward to a new day. A day when Jesus returns to establish His kingdom on earth. An earth that has been transformed.