Authors of fictional works intended to be deceptive historical accounts would never implicate themselves by creating a false narrative that is embarrassing to themselves.
The authors of the Bible record details that are embarrassing to themselves. This is evident in things like wars. Every war is recorded win or loose. Modern civilizations typically only record either the events that are favourable or record the events in a favourable way. For example in U.S. history how many wars according to them have they lost? We either don't hear about the ones they've lost or they are taught in a skewed manner. One detail is D day. If you live in Canada you are taught that the Canadians were the ones who stormed the beaches and won the victory. If you live in the U.S. You are taught it's the American troops. This false sense of pratriotism cannot be trusted. I personally only find a record of history accurate and believable if failure and losses are reported as well.
Other embarrassing details are found in the gospels. One such example is at the resurrection. We know that these books were authored by men, we also know that in that era a woman's testimony was not considered trustworthy, it would not stand up in a court of law. The authors record that it was the women who found the tomb empty. If they were writing a fictional account which they were trying to pass off as truth they would have recorded that the men found the tomb empty. To add to that they also recorded that while the women were finding the tomb empty the men were hiding because they were afraid for their lives while the women were the brave ones. No man writing a fake story which he would want believed in that culture would ever have written these things unless they were true.
New Testament scholars tell us the book of Mark is the account of Peter dictating to Mark who wrote it down. In it he includes his betrayal and denial of Jesus in great detail. Why would Peter do this if he was lying? These details are one sure proof that the Bible is truthful.