Heart to heart shows a willingness to listen (3)
I believe the answer is:
ear
'a willingness to listen' is the definition.
(I've seen this before)
'heart to heart' is the wordplay.
'heart' says the answer is hidden in the clue (I've seen 'heart of' mean this).
'EAR' is hidden within 'heart'.
'shows' is the link.
(Other definitions for ear that I've seen before include "Lend one and listen" , "Go astray" , "Auricle" , "Speculator ignoring British" , "Musical ability" .)