Why do we believe it?

Here's how and why it all happened if that helps you....

After Lord Buddha the teaching was kept alive by the monks who learned and kept it by heart, they did it in few different ways. Some individuals kept it all while some learned chapters.

Time to time they would come together for a reciting. This would be called a Council, It is essentially a global gathering of monks who have the teaching by heart. Here they would each recite the teaching that they have kept. This was done to clear any doubts and clean the error as all the other are listening and chanting too.

In Sri Lanka the same tradition went on until an all island drought came. Some monks went to india and some stayed in the island. They hardly saved themselves but a lot of Arahats passed away because of the drought. They decided that the Oral tradition is not reassuring as they saw it first hand. So they did another Gathering or a "Council" and this time they wrote teaching. This Became the "Tipitaka" of Theravada.

So the whole process was done right and transparently.

This is how it happened. I should remind you that if one chooses to put away the tipitaka he or she ends up with nothing else but his or her own version of things that his or her mind construct to benefit. Without the tipitaka there is no Buddhism left to follow.

I must say that one thing you said is wrong. It is not a Buddhist thing to make our own version. I agree that we all interpret the teaching in our own way, but one should not make personal beliefs. But the teaching is open to different interpretations as we all are with different wisdom and intelligence.

Namo Buddhaya!

Tripitaks especially those first two ones Sutra Pitaka and Vinaya Pitakas they are written after the tradition of oral trasmission of the teaching of Buddha.

Even in these days in certain asian buddihst tradition, written transmission is not conducted because an individual practicionals awareness is all different to person to person. They are guided individually.

It applies to Buddhas teaching when he was alive the Dharma was trasmitted oral only, and the 10 deciples memorized all those and were written in Pitakas from their perfecrt recollections after the first council. You can highly rely on their recollections. They are telling the truth in simple terms.

With regards to how do you know? Once you see the glimpse of the truth And your world changes upside down with shedding of tears you just know there is no difference in writings of Dharma. Buddha nature or Buddha seeds are same regardless of who, when, where realizes.

Tripitakas are diamond jewel where direct descriptipns of Buddha are found.

This question cannot be "answered" because I believe it hits us humans, straight at the core of our faith and understanding of everything in general.

Buddhism is just one of the routes to enlightenment. It is not a religion. But unfortunately some people take it as such because they are skewed to "faith". It gives them a false sense of "hope". A hope that says there is a "savior" among us in our hearts. What we don't understand is that spirituality is actually subjective. How we realize the ultimate, is up to us.

I don't wish to go through a whole load of drivel just to make you understand that belief and faith works everywhere in our world. It happens with all religions, politicians, social media, advertising, add your own list here. Belief and blind faith seeps through our very roots in society.

There may be a point in questioning beliefs but ultimately that is just to ground yourself in reality and see things as they are. You cannot really, totally change what's around you. I'd suggest using common sense and questioning for yourself at best along with practice.

It should be verified through pratice by what you experience at the experiential level. If you experience something you know for a fact it is true.

Normal you should:

1. Learn the theory (Pariyatti)
2. Practice what you learned (Patipatti)
3. Experience what you learned why which you verify the teachings (Pativedha)

When you reach 3 your doubts will be cleared as you know for yourself.