Come on, how many people have enough knowledge to verify something related to bitcoin?! The believe system is 99.9% based on the fact that bitcoin has never been compromised.
90% of the time you just have to understand how to sign message and confirm it, or see the wallet balance before you make a deal with someone claiming to have 100 BTC, or require proof for their claim etc. it's as simple as that. maybe you don't know how blockchain works, but at least you should know how to avoid scam.