It's pretty much UP to you , If you want to trust , you trust otherwise just don't. No one is going to oblige you to trust anything, but logically... how could someone trust the government (If you do , idk) and not trust something decentralized ?
Trust begets trust.Lots of people have invested their time and money in bitcoin because they believe in it.We must believe in it because such a huge investment of resources is not going to end but will only grow with time