Love promotion to start commotion (3)
I believe the answer is:
ado
'commotion' is the definition.
(ado is a kind of commotion)
'love promotion to start' is the wordplay.
'love' becomes 'o' (love means zero in tennis).
'promotion' becomes 'ad' (short for advert).
'to start' is a charade indicator (letters next to each other).
'o' after 'ad' is 'ADO'.
(Other definitions for ado that I've seen before include "Fuss, difficulty" , "'Much ... About Nothing, Shakespeare play (3)'" , "Goings-on" , "excitement" , "Fuss, trouble" .)