Keen on local couple getting a hearing (4)
I believe the answer is:
into
'keen on' is the definition.
(I've seen this before)
'local couple getting a hearing' is the wordplay.
'local' becomes 'in' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'couple' becomes 'two' (a couple can mean two of something).
'getting a hearing' shows a homophone (sound like).
'two' is a homophone of 'to'.
'in'+'to'='INTO'
(Other definitions for into that I've seen before include "digging" , "Showing enthusiasm for" , "Four this twelve is three" , "Keen on (informal)" , "Keen on, colloquially" .)