First off, a person has to decide whether they want the truth, or whether they want their own way. God has given people what they wanted before (1 Kings 22:19-23), and if a person is not completely sincere in their desire to find the truth, they'll find exactly what they want to find.
One must also decide to trust God, and take Him at His word. He made more promises about His word than any other thing in the Book; it may sound like circular reasoning to believe the Bible because the Bible says that the Bible is right, but the element that changes the entire equation is faith. The people that don't believe that God preserved His words in one Book don't apply faith in God Himself and His ability to work through fallible man to accomplish what He
promised.
When a person gets to the point where they seriously WANT the truth, and they BELIEVE God and what He said about His words, then the rest is easy. Spend some time on this forum, feel free to ask questions, and above all, search the Scriptures. Get e-Sword (or if you're Saved, get MacSword
) and use it to search the Book for yourself. There is nothing more powerful than the built-in definition and cross-reference system in the King James Bible; there is nothing like it in the world.
God bless, and I hope that you will accept help from people who have been where you are and have been utterly convinced, beyond all doubt, reasonable or not, that the King James Bible is God's perfect, pure, preserved and inerrant word, given by inspiration of God.