It has been long that I have done this, it is very possible. If you want to buy or sell from or to ERC20 or BSC, just go to your trust wallet, click on dex, dex will be seen at the lower part of the wallet user interface, click on it. Choose the tokens you want to convert from and the one you want to convert it to, write the amount and press 'swap'. Make sure you have the an amount of ethereum gas or BSC fee that is needed for the swapping.