Truth is what lets you predict the future state of the world. The better the predictions, the closer you are to "the truth". Physicists are very careful to understand the uncertainties in what they know and only say its "true" and publish the results when those uncertainties 5 or 6 or 7 sigma. Their predictions work almost always but are limited to a very small slice of reality. Other sciences move farther from this ideal and are less likely to be stating "the truth".