Genuine leader of men in province (5)
I believe the answer is:
realm
'province' is the definition.
(thesaurus)
'genuine leader of men' is the wordplay.
'genuine' becomes 'real' ('real' is associated in meaning with 'genuine').
'leader of' suggests taking the first letters.
The initial letter of 'men' is 'm'.
'real'+'m'='REALM'
'in' acts as a link.
(Other definitions for realm that I've seen before include "King's domain" , "Land under a king or queen" , "where ruler holds sway?" , "Country" , "Kingdom or sphere" .)