Love quiet reformed person in penal establishment (4,6)
I believe the answer is:
open prison
'penal establishment' is the definition.
'love quiet reformed person in' is the wordplay.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'quiet' becomes 'p' (music symbol for 'piano').
'reformed' is an anagram indicator.
'person'+'in'='personin'
'personin' is an anagram of 'enprison'.
'o'+'p'+'enprison'='OPEN PRISON'
(Other definitions for open prison that I've seen before include "jail" , "Gaol for mild offenders" .)