"Truth" can be understood as a statement that accurately represents existence.
When discussing the concept of truth, we're typically referring to the accuracy with which concepts and statements reflect reality. Truth is not just about the objective state of affairs, but rather how well our ideas and language accurately represent them.
It's important to recognize that absolute accuracy is not possible in this context, as concepts and language always have a limited scope and can only represent reality to a certain degree. For example, while it may be true that a grain of salt contains 10 quadrillion atoms, our understanding of atoms could be expanded to include subatomic particles, and other aspects beyond just quantity could be considered for greater accuracy. However, the notion of arriving at an absolutely accurate statement without the limitations of language remains an interesting philosophical debate.
Nonetheless, in everyday usage, truth should be understood to refer to the degree of accuracy in representing reality. The accuracy of a statement can be evaluated by considering how it was developed and its source. For further reading on this subject, I would recommend "The Relativity of Wrong" by Isaac Asimov.