Now love bother (3)
I believe the answer is:
ado
'bother' is the definition.
(ado can mean a commotion or fuss)
'now love' is the wordplay.
'now' becomes 'AD' (AD, Anno Domini, as opposed to BC, Before Christ).
'love' becomes 'o' (love means zero in tennis).
'ad'+'o'='ADO'
(Other definitions for ado that I've seen before include "Pother" , "flapping" , "Fuss or bustle" , "stew is provided" , "hoo-hah" .)