Perhaps you believe in God.
Perhaps you believe in Allah.
Perhaps you believe in Buddha.
Perhaps you believe in Krishna.
Perhaps you believe in Wotan, Horus or Zeus?
Well, not if you were born in - respectively -
the land of the Vikings, ancient Egypt or in the days of the ancient Greeks.
Point is: where and when you were born greatly decides what you belief.
Mostly because your parents and other leaders tell you what to belief.
If you would leave out what your parents, teachers, media and government told you: what would you truly believe?
To refrase that for christians: if no one had ever told you about the Bible and the Gospel, would you still put your faith in Jesus Christ? (Same question for other religions)
Looking forward to reading your thoughts in the comments!