Saint has a new date thats fixed (6)
I believe the answer is:
stated
'fixed' is the definition.
(I've seen this in another clue)
'saint has a new date' is the wordplay.
'saint' becomes 'st' (abbreviation).
'has' is a charade indicator (letters next to each other).
'a new' indicates an anagram.
'date' with letters rearranged gives 'ated'.
'st'+'ated'='STATED'
'thats' is the link.
(Other definitions for stated that I've seen before include "Declared or asserted" , "Specified" , "Clearly expressed" , "Uttered, expressed in words" , "Expressed, detailed" .)