Tell, once again, a false tale (6)
I believe the answer is:
relate
'tell' is the definition.
(as in to tell or relate a story)
'once again a false tale' is the wordplay.
'once again' becomes 're' (prefix in verbs).
'a false' is an anagram indicator.
'tale' anagrammed gives 'late'.
're'+'late'='RELATE'
(Other definitions for relate that I've seen before include "Marriage Guidance - report" , "Empathise" , "Recount" , "Connect in Tralee" , "Tell - the marriage guidance people" .)