How does selling of BEP20 tokens work? Does there have to be a buyer?

Hey guys, I've tried finding some information on this, but couldn't find it anywhere.

When the time comes and you want to "sell" BEP20 tokens on trustwallet via e.g. pancakeswap, how does it actually work? Let's say your 1000$ portfolio goes up to 10000$ and now you want to swap back, I imagine this would be like on any exchange and there would have to be someone on the other end "buying" 10000$ of your token with BNB at that moment? If not, where is the BNB coming from you get when you swap it? Because somebody is losing money at that point.