I and my younger brother have been learning about honesty from our parents since we were young.

>>Correct
So, I also think honesty is the most important thing. Because there are three main reasons.

>>So, I also think honesty is the most important thing because of three main reasons. 

First, because lies bring about bigger lies.
OR
>>First, lies lead to bigger lies.

If you keep telling bigger lies, you may not be able to handle it on your own.
You may also have to bear the consequences yourself

>>Correct

Of course, I know it's hard to way what you've done wrong or what you've made a mistake.
>> It's hard to admit when you've done something wrong

But to be honest, I think it's more important to fix it, and I think you can prevent situations where it can get worse when you can.
OR
>>But it's more important to fix it and prevent the situation from getting worse.

Second, if you think based on the first reason, if you don't be honest, you end up being an unreliable person.
OR
>>Second, if you're not honest, you become an unreliable person. 

People must not lie nonstop, but if they continue to lie or if they are not responsible for what happened behind them, they will eventually develop a perception that they are unreliable.
OR
>>People may not lie constantly, but if they continue to lie or avoid taking responsibility, they will be seen as unreliable.

Finally, because I think honesty is based on everything.
OR
>>Finally, I believe honesty is the foundation of everything.

I think honesty is the basis for everything a person lives.
>> It's the basis for everything in people's lives. 

When calculating things, people calculate things honestly and proceed with the work each other based on honesty.

>> When calculating things, people calculate things honestly and proceed with the work of each other based on honesty

OR

>> People evaluate others based on their overall honesty, and then they work with them accordingly.

If honesty is based on everything like that, I think a clean society will be created by itself.

>>Correct