We know how much God loves us, and we have put our trust in his love.
God is love, and all who live in love live in God, and God lives in them. And as we live in God, our love grows more perfect. So we will not be afraid on the day of judgment, but we can face him with confidence because we live like Jesus here in this world.
Such love has no fear, because perfect love expels all fear. If we are afraid, it is for fear of punishment, and this shows that we have not fully experienced his perfect love. We love each other because he loved us first.