I am sorry, Drifter. The very original manuscripts of the books that compose the Bible as they were - so we Christians believe - first inspired by the Spirit upon human men to write? That I would not know. I find it hard to believe they would even still exist today.
You seem doubtful, sir, if I may say that with all due respect, and are not "certain", such that so far you know only to believe, but do not have that "head knowledge" that Jesus is real and that He is the way to eternal life. Am I understanding this correctly?
All I can tell you is, I am not sure a person can ever truly, truly KNOW, with 100% accuracy. For me, I choose to believe, because I just cannot see it any other way. I cannot imagine life without trusting and believing in Jesus Christ, but I am not going to pretend to be all super religious and claim that I KNOW Him - that He is Son of God and Savior of mankind from its evils and can grant us immortality and forgiveness of sins - to be proven and as real as the things we physically see around us on planet Earth every day. There's a reason it is called faith, and not science, after all.
And if my beliefs are indeed not in vain, I suppose I will find in the end that it was the Spirit Himself who witnessed to me and caused me to believe as I do now, so perhaps I never actually chose for myself, completely of my own accord, to believe. But rather, because He already proved Himself to me.
I hope I have not made incorrect or insulting assumptions about you with this post, or rambled on about myself too long?