Very keen to help penning verse (4)
I believe the answer is:
avid
'very keen' is the definition.
(I've seen this before)
'help penning verse' is the wordplay.
'help' becomes 'aid' ('aid' can be a synonym of 'help').
'penning' means one lot of letters goes inside another.
'verse' becomes 'v'.
'aid' going around 'v' is 'AVID'.
'to' acts as a link.
(Other definitions for avid that I've seen before include "Impassioned about diva" , "Showing a very keen interest in something" , "Greedy or eagerly desirous" , "Fanatical" , "Greatly desirous" .)