Basic to believing in God is believing! This seems to state the obvious, but some will not accept the reality of God without “proof.” “Proof” is evidence that establishes a truth leaving no room for doubt, no room for faith. That is not how God has chosen to present himself, yet. However, there is a preponderance of evidence making denial of God's existence suspect of dishonesty and hidden motives, possibly rooted in pride and selfish desire (Psalm 14; Romans 1:18-32).
“The heavens declare the glory of God; the skies proclaim the work of his hands” (Psalm 19:1). Reason, commonsense, and scientific evidence declare something does not come from nothing. Leave out God or some eternal being and the existence of this temporal world is unexplained. Evolution cannot explain the beginning of existence. Neither can it explain the complexities of the cosmos that demand intelligent design, not blind chance. Some simple systems cannot function or exist without each part interacting; the system cannot wait for any one of its parts to “evolve.” Neither can evolution explain things of beauty that serve no function; beauty calls for creativity, not survival of the fittest.
Proof? No. A preponderance of evidence? Yes—for now anyway, “for we walk by faith, not by sight” (2 Corinthians 5:7).