Order to cover one single love song (1,4,3)
I believe the answer is:
o sole mio
'song' is the definition.
(I've seen this before)
'order to cover one single love' is the wordplay.
I cannot quite understand how this works, but
'order' could be 'o' (abbreviation e.g. in British honours OM, OBE etc.) and 'o' is located in the answer.
'one' could be 'sole' (synonyms) and 'sole' is found in the answer.
'single' could be 'i' (one) and 'i' is present in the answer.
'love' could be 'o' (love means zero in tennis) and 'o' is present in the answer.
A single letter 'm' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for o sole mio that I've seen before include "Italian tune" , "Italian song anglicised as It's Now or Never" , "Italian original of Presley's It's Now or Never" , "It's Now or Never used this Italian song" , "Air" .)