The word truth can be used several ways, just as 'folk'. But it often involves an equivocation when just tossed about. When capitalized and put in quotes, it is usually meant as dressed up word for 'fact'.

If 'facts' are known in some matter, 'truth' means honestly and accurately acknowledging facts.
A lot of what people like to wave about as truth is merely some subjective opinion on some abstraction. It gets kinda slippery.