Literally understand:
Although the rain in the sky covers a wide area and moistens everything on the earth, it can't moisten the rootless grass, because the grass absorbs water through the roots, and the rootless grass can't moisten even if it is soaked in water; Although Buddhism is everywhere, including all aspects around us, there is no chance for those who have no chance to be redeemed in this life.
This sentence promotes a kind of fate. Love is incomplete, how can we be together? Without love, we will not be happy together.