A love note enclosed produces excitement (3)
I believe the answer is:
ado
'excitement' is the definition.
(I've seen this before)
'a love note enclosed' is the wordplay.
'love' becomes 'o' (love means zero in tennis).
'note' becomes 'd' (musical note).
'enclosed' means one lot of letters goes inside another.
'a'+'o'='ao'
'ao' going around 'd' is 'ADO'.
'produces' acts as a link.
(Other definitions for ado that I've seen before include "Fuss, trouble" , "Rapid bustling commotion" , "'Much ... About Nothing, Shakespeare play (3)'" , "flapping" , "Busy activity, trouble" .)