Making an effort can be distressing (6)
I believe the answer is:
trying
I believe this is a double definition.
'making an effort' is the first definition.
(I've seen this before)
'be distressing' is the second definition.
(thesaurus)
'can' acts as a link.
(Other definitions for trying that I've seen before include "Bothersome" , "undertaking" , "Annoying; sampling" , "Making an effort, or straining one's patience" , "Tiresome" .)