This is the 434th most frequent Greek word.
αλήθεια
Truth.
Here, "αλήθεια" is used as a noun meaning "truth," referring to the factual situation.
Η αλήθεια είναι πως έφτασα αργά.
The truth is that I arrived late.
In this sentence, "αλήθεια" is used as an adverb meaning "truly" or "really," to emphasize the question's sincerity.
Αλήθεια, ξέρεις τι ώρα είναι;
Truly, do you know what time it is?
Here, "αλήθεια" is again used as a noun but metaphorically to signify a profound understanding or realization.