Soldier initially believed the French story (7)
I believe the answer is:
parable
'story' is the definition.
(parable is a kind of story)
'soldier initially believed the french' is the wordplay.
'soldier' becomes 'para' (para is a kind of soldier**).
'initially' says to take the initial letters.
'the french' becomes 'le'.
The first letter of 'believed' is 'b'.
'para'+'b'+'le'='PARABLE'
(Other definitions for parable that I've seen before include "Instructive story" , "Leap bar poorly for a biblical story" , "Sower, for one" , "scripture lesson" , "Moral tale" .)