Positive statement senoritas need translating (9)
I believe the answer is:
assertion
'positive statement' is the definition.
(positive or affirmative statement)
'senoritas need translating' is the wordplay.
'need translating' indicates anagramming the letters.
'senoritas' with letters rearranged gives 'ASSERTION'.
(Other definitions for assertion that I've seen before include "Emphatic declaration" , "Confident statement of fact" , "Confident declaration" , "Notarises (anag)" , "Claim" .)