What are the secrets of bible that are not yet known but rumors are created if they are out, will destroy Christianity?

They're secret. If it suddenly emerged the the Bible had been forged by a few people over a few hundred years, with evidence of forgery stacked up as high as Everest, that would be ignored by a pretty fair proportion of Christians, and some of them would go out of their way to lie about the evidence.

Any number of scholars have been aware for the best part of 180 years that some of the material attributed to Paul was almost certainly written by someone else. That's like water off a duck's back.

Answer : Revelation 17:16

16 And the ten horns that you saw and the wild beast, these will hate the prostitute and will make her devastated and naked, and they will eat up her flesh and completely burn her with fire.

World Government will Eat the Empire of False Religion (Including False Christianity)

Well, there are two types of Christianity.. The False, and the True

The False Christianity is symbolized by the Great Harlot, Babylon the Great

Revelation 17:3-5

Babylon the Great is the Empire of False religion, including the False Christianity.

How did we know that there are false Christians?

Jesus did warn us in Matthew 7:15

15 “Be on the watch for the false prophets who come to you in sheep’s covering, but inside they are ravenous wolves.

And Jesus told us to take the narrow gate (True Christians)

Matthew 7:13

13 “Go in through the narrow gate, because broad is the gate and spacious is the road leading off into destruction, and many are going in through it;

So if you think that you are in a false religion/Christianity, we are ordered to flee from her:

Revelation 18:4. 4 And I heard another voice out of heaven say: “Get out of her, my people, if you do not want to share with her in her sins, and if you do not want to receive part of her plagues.

Here is a secret that I only know about.

While I was doing an in-depth study of the clean and unclean food and hygiene laws established over 3500 years ago in the Book of Leviticus I made a discovery. These laws and instructions have been based all this time on someone's working knowledge of the germ theory of disease and the modern human body and other advanced fields of science unknown to mankind at that time and some fields of science still unknown to mankind today. That means the advanced scientific knowledge hidden in this ancient Biblical scripture could not have originated from any human mind on earth at that time and had to originate from a non human scientific mind for humans to follow. My discovery also brings to light mankind's misinterpretation of this scripture and giving them the unscientific religious interpretations we still think they mean today due to our lack of scientific knowledge to properly interpret what is written.

When evidence that the Bible has major problems comes out, Christians simply deny it. There is nothing that anyone could say that would make fundamentalist Christians stop believing. Their beliefs are impervious to evidence and information.

This will not destroy True Christianity:

THE ADOPTION THEORY:

Christians first taught that God adopted Jesus when Jesus was baptized. Mark is the first Gospel and did not report a virgin birth. The virgin birth story first appeared 40 years after Jesus's death.

Joseph was Jesus' biological father.

The secret of bible: why anyone would over the age of 8 would believe such utter nonsense?

That's the secret of the bible.

If it were revealed that the whole thing was written as a joke on the human race, but the human race missed the punchline and fell for it hook, line and sinker. That would cause some pretty significant butthurt (and it would be funny as hell too).

If someone provides an answer with an actual "secret" about the Bible wouldn't that defeat the purpose or description of said secret?

Additionally, the Bible within its pages encourages thought and questioning. It discourages blind faith. Whereas many Christian denominations convinced their flocks that God views the asking of questions as a lack of faith.

That could not be more further than the truth. That runs contrary to what God's Word The Bible teaches.

Luke 11:9 So I say to you, keep on asking, and it will be given you; keep on seeking, and you will find; keep on knocking, and it will be opened to you. 10 For everyone asking receives, and everyone seeking finds, and to everyone knocking, it will be opened

Proverbs 14:15 The naive person believes every word,But the shrewd one ponders each step

James 1:5 So if any one of you is lacking in wisdom, let him keep asking God, for he gives generously to all and without reproaching, and it will be given him.

The Bible did foretell a time when true knowledge or understanding of the Holy Scriptures would increase

Daniel 12:4 As for you, Daniel, keep the words secret, and seal up the book until the time of the end. Many will rove about, and the true knowledge will become abundant

Jehovah God wants everyone to be able to understand His message. The person who has knowledge could then have understanding. If we grasp it and appreciate God's Word The Bible and what's found therein we can apply it in our life and display wisdom.

Proverbs 2:1 2 My son, if you accept my sayingsAnd treasure up my commandments, 2 By making your ear attentive to wisdomAnd inclining your heart to discernment; 3 Moreover, if you call out for understandingAnd raise your voice for discernment; 4 If you keep seeking for it as for silver,And you keep searching for it as for hidden treasures; 5 Then you will understand the fear of Jehovah,And you will find the knowledge of God. 6 For Jehovah himself gives wisdom;From his mouth come knowledge and discernment

A person can better know the true meanings of Bible verses if he or she meditates on them while carefully saying Hail Marys.

Not only Christianity but the whole world, when the Messiah comes and everyone still living will be united in one faith!