When you talk about trusting a coin, you have to look at different achievements of the project working with the token or coin, the background and level attained. To me, Ethereum is a base token and can't be compared to BNB, unless there's better and strong competition from BNB. I go with Ethereum.
I also believe that you can not put these two coins in the same row, since they have completely different functions. BNB is the coin that created exchange Binance and the value of which is very closely related to the functioning of this exchange. And Ethereum is the basis for most cryptocurrency projects.