Don’t trust any sources unconditionally, to call it truth. You can decide for low stakes things, it can be worth it to act as though some things to trust are true, but all you can really know is that you exist as a thinking being. Practical knowledge which you use, in the basis of probabilities, to navigate the empirical world, is not synonymous with truth. And even in the empirical world’s practical knowledge, it is very low probability that the world is flat. The methods of science and experimentation are good methods for finding good probabilities for empirical knowledge, and they demonstrate that the Earth is very likely round.