Answer
Salam (Peace) Dear Reader,
Thank you for your question and for contacting Ask About Islam.
Initially, I must say that there is a logical contradiction in your question because “praying” is one way of acknowledging that God exists.
Therefore, as a quick answer to your question, the Quran does not specifically contain a verse that shows all a curious person needs to do is pray to find out if God exists; not only because of the aforementioned reason but for many other reasons, which I will be discussing in the following paragraphs.
To begin with, God is the author of the Quran and anyone reading it with an open mind will realize that, whether reading the original text in Arabic or a translation. This is simply obvious because no human writes in this fashion and with such confidence by saying what means:
{Surely I am Allah, there is no god but I, therefore serve Me and keep up prayer for My remembrance} (Taa-Haa, 20:14)
In another verse, where God is talking to Moses:
{O Moses! surely I am Allah, the Mighty, the Wise} (An-Naml, 27:10)
When opening any print of the original Quran in Arabic, we will not find an author. Different translations have different authors but the Arabic mentions no author because God, Allah in Arabic, is the author.
Allah talks to us through the Quran and tells us to supplicate to Him whenever we need Him:
{And your Lord says: Call upon Me, I will answer you…} (Ghafir, 40:60)
This means if we sincerely ask from God, He shall answer our prayer if we obviously ask for something that is not harmful to us or others.
Therefore, here comes your answer, all a curious person needs to do is pray or supplicate sincerely to God for guidance. If in doubt, one may say: “If You are out there, guide me!”
This must come from the heart of the seeker and it must be in one’s own language with such a devotion that tears flow from the eyes.
There is no barrier between God and us and no one should tell us what to say when seeking His guidance. We may talk to Him directly and reveal our thoughts; and it does not have to be said out loud. God tells us what means:
{And if you utter the saying aloud, then surely He knows the secret, and what is yet more hidden.} (Taa-Haa, 20:7)
Furthermore, God addresses all mankind in the Quran telling them to believe in Him and His apostle, and to worship Him alone:
{O mankind! serve your Lord Who created you and those before you so that you may guard (against evil).} (Al-Baqara, 2:21)
{O people! surely the Apostle has come to you with the truth from your Lord, therefore believe, (it shall be) good for you; and If you disbelieve, then surely whatever is in the heavens and the earth is Allah’s; and Allah is Knowing, Wise.} (An-Nisaa, 4:170)
{O people! surely there has come to you manifest proof from your Lord and We have sent to you clear light (guidance).} (An-Nisaa, 4:174)
{Say: O people! surely I am the Apostle of Allah to you all, of Him Whose is the kingdom of the heavens and the earth there is no god but He; He brings to life and causes to die therefore believe in Allah and His apostle, the Unlettered Prophet who believes in Allah and His words, and follow him so that you may walk in the right path.} (Al-Aaraf, 7:158)
{O mankind! there has come to you indeed an admonition from your Lord and a healing for what is in the breasts and a guidance and a mercy for the believers.} (Yunus, 10:57)
{Say: O people! indeed there has come to you the truth from your Lord, therefore whoever goes aright, he goes aright only for the good of his own soul, and whoever goes astray, he goes astray only to the detriment of it, and I am not a custodian over you.} (Yunus, 10:108)
{O mankind! remember the favor of Allah on you; is there any creator besides Allah who gives you sustenance from the heaven and the earth? There is no god but He; whence are you then turned away?} (Faatir, 35:3)
{Say: O people! I am only a plain warner to you.} (Al-Hajj, 22:49)
{O mankind! Surely We have created you of a male and a female, and made you tribes and families that you may know each other; surely the most honorable of you with Allah is the one among you most careful (of his duties towards Allah); surely Allah is Knowing, Aware.} (Al-Hujuraat, 49:13)
My advice to you is to read the Quran with an open mind without forgetting to let it reach your heart. You will not only understand that God exists but you will find many answers that you have been wondering about.
Take some time in the evening when it is quite and there is no one to disturb you, and then ask God for guidance. The truth is clear, seek it!
I hope this answers your question.
Salam.