Señora's complicated motives (7)
I believe the answer is:
reasons
'motives' is the definition.
(I know this)
'senora's complicated' is the wordplay.
'complicated' indicates anagramming the letters (a complex or confusing ordering of the letters).
'senoras' with letters rearranged gives 'REASONS'.
(Other definitions for reasons that I've seen before include "Rational motives" , "Justifications or motives" , "Motives, rounds" , "Thinks logically" , "Ness oar (anag.)" .)