You are not the only one. 99% of people have no idea what “a Bitcoin” even is. It goes over their head when you try explaining it. The reality is, on the front end or at least from a consumer point of view, it is simply virtual money/currency. That’s it. It is digital cash you can use to buy stuff.
I think people do not believe in it mostly because they fail to understand the structure behind it. See, Bitcoin is essentially built or programmed just like physical gold. There is only a certain amount of gold available and it becomes harder to mine, thus more valuable over time. Bitcoin is the exact same, but most people are unaware of this, hence why they don’t believe in it..