Fund to conclude with expression of pain (5)
I believe the answer is:
endow
'fund' is the definition.
(I've seen this before)
'conclude with expression of pain' is the wordplay.
'conclude' becomes 'end' (I've seen this in another clue).
'with' says to put letters next to each other.
'expression of pain' becomes 'ow'.
'end'+'ow'='ENDOW'
'to' is the link.
(Other definitions for endow that I've seen before include "Pay to found" , "Provide with a permanent income, say a school" , "provide permanent finance for ..." , "Bequeath or give an income or property to" , "Give funding to establish (something)" .)