Who means to reveal where the heart is? (4)
I believe the answer is:
home
'where the heart is?' is the definition.
(I've seen this in another clue)
'who means to reveal' is the wordplay.
'to reveal' indicates a hidden word.
'HOME' can be found hidden inside 'who means'.
(Other definitions for home that I've seen before include "Place of origin" , "Last line of defence in World War II" , "It's where the heart is, it's said" , "Habitual abode" , "birthplace" .)