One of the classical demonstrations of God’s existence is the so-called argument from desire.
It can be stated in a very succinct manner as follows. Every innate or natural desire corresponds to some objective state of affairs that fulfills it.
We all have an innate or natural desire for ultimate fulfillment, ultimate joy, which nothing in this world can possibly satisfy. Therefore there must exist objectively a supernatural condition that grounds perfect fulfillment and happiness, which people generally refer to as “God.”