I suppose that the question is less on whether we believe that God exists and more on whether we want Him to exist. The pre-Christian mind needs to conclude that "God exists and He rewards the seeker" (Hebrews 11:6). To be at that point one must have had a wanting for the benevolence that only a God can provide. The pre-Christian has to hope. They are described as "without hope or God in this world." If they always suspect, doubt, roadblock, stall, then the message of the Gospel will not meet eager ears. But they must hope, not for world peace or a cancer free Aunt Betty, but they must hope for the rewards of God.
Many people think that money will solve the calamity of their life. They start to imagine a rich uncle who will die and they will inherit the answer. They buy lottery tickets in flagrant abuse of the odds because the "answer" is money and they have hope. God can answer many of those calamities better than money but no one can see how and many Christians live with such similar calamities that it gives a negative testimony to the lost. But Hell, on the other hand, can't be fixed by money or cosmetic surgery. Forgiveness of sins cannot be accomplished with a Roth IRA. A tax-free lottery win can bury you in the Benjamins but you'll still be damned, and to be more clear, damned eternally. To create a hope that leads a soul to grace we have to preach a problem the answer to which only God controls. The testimony of our lives must be a testimony of righteousness gained and lived with the joy of Life Eternal. No more of the entertaining church that "seekers" (who are not seekers) will attend and decide to add bits of the Christian religion to their family's sense of purpose. They haven't sought God. They have no hope of God's answer in the Lord Christ for the sins of their benighted souls.
"Faith comes by hearing and hearing by the preaching of Christ." (Romans 10)
"Faith is the assurance of things hoped for." (Hebrews 11)
The kind of hope we offer and that we create in the hearer is the kind of faith we get from our "converts" Is it any wonder that the Church today is filled with unregenerate souls? What does your church offer in lieu of forgiveness and Life Eternal? Belonging? Neat culture? Modest dress code? Ethical authority? Family protection? Big answers to all your questions? Patriarchal humbug? A youth group pop replacement? Ritualisic juju?
I know, I know, not everyone drawn by these things has done so with such a shallow expectation. Many believe that somehow, somewhere in the magic back rooms of THE CHURCH the salvation machines are working overtime to guarantee salvific grace will ooze out of the pew and leech miraculously into their's and their children's unsanctified behinds. This is Christianity folks, not Baal worship. All the belonging, all the performance, all the passion plays are but filthy rags. You family's service in the temple is pointless. The church has no grace to give.
The word is near you, on your lips and in your heart (that is, the word of faith which we preach); because, if you confess with your lips that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved. For man believes with his heart and so is justified, and he confesses with his lips and so is saved. The scripture says, "No one who believes in him will be put to shame." For there is no distinction between Jew and Greek; the same Lord is Lord of all and bestows his riches upon all who call upon him. For, "every one who calls upon the name of the Lord will be saved." Romans 10:8-13
But to all who received him, who believed in his name, he gave power to become children of God; who were born, not of blood nor of the will of the flesh nor of the will of man, but of God. John 1:12-13
Jesus died for your sins. When you hope against hope that that is precisely what He will address in you, you stand ready for the Faith that saves.