The question is, are we brave enough to challenge our own beliefs.
I agree that we all should challenge our own beliefs and that includes me too.
Some reasons that I believe that the Bible is telling the truth about God are:
1. Bible prophesies written by many authors over a very large span of time with an entire nation bearing witness that it was their primarily their ancestors that heard from God. Why is this last part important? Well, it would be one thing if one person invented a religion and got a lot of followers that just believed what the person said. It's another thing to have a whole nation having this large number of writers spread over a large amount of time, handed down as historical figures that, in some cases, have some (limited) evidence in archaeology as well. The Bible presents a unified portrayal of the same God. His character as revealed at the beginning of the Bible is the same as at the end, although the revelation of His Person becomes more in depth as one progresses through the Bible towards the end.
2. Archaeological evidences support the Bible's historical records. Although they are limited, they don't disprove the Bible.
3. It all makes sense.
4. God has convicted me of sin in a way that I do not experience with people. I have felt sorry for things I've done to people, but when God convicts me of sin, it is usually with a deepened understanding of His absolute goodness combined with His rights as Creator to rule. It's probably the closest thing to His presence that I have personally experienced. Also, this isn't the same as feeling guilty because at the same time He helps me to see how wonderful it is that Jesus took my place and I'm seen as one who is righteous in God's eyes, even though I'm sinful in actions. It's very different from how people would view being guilty before God if they don't have Jesus as their Advocate. So, just to make this clear, this is something God reveals to me, not something that I am imagining, which is one reason why I have kind of an unshakeable faith. I think this explains it better. What if you're riding a bike and you see that you're headed for a ditch. You know the concept that you're going to fall into the ditch, but until you actually fall and feel yourself hitting the ground, the concept remains in your mind. In the same way, these concepts are in my mind because I know that they are in the Bible, kind of like knowing you're headed for a ditch. But when you actually meet the ground, that is more like how God suddenly speaks to your heart, as though He is saying to your heart, "You're the man." (or woman

). And also, impressing the truth of Jesus. And this is something unlike anything I think I've experienced in any other area of life. To try to put it in simpler terms, God speaks to peoples hearts about their sin and their need for reconciliation with Him through the Bible. There is else like this that I have come across. People either suppress this or turn to Him, but He does reveal Himself.
5. Answers to prayer and Divine interventions, which I'm sure you all think are coincidences.
6. The Bible gives the best and most thorough explanation (I believe) for the existence of problems in this world and yet reveals God to be entirely good--it is not His fault that people have turned to our own ways.
7. My experiences with the Bible and God have been similar to many others' experiences.
8. There's probably more. I just can't think of them right now.