Trouble a nobleman with a saintly heart? (6)
I believe the answer is:
pester
'trouble' is the definition.
(thesaurus)
'a nobleman with a saintly heart?' is the wordplay.
'a nobleman' becomes 'peer' (peer is a kind of nobleman).
'with' is an insertion indicator.
'a saintly heart?' becomes 'st' (I can't explain this - if you can you should believe this answer much more).
'peer' enclosing 'st' is 'PESTER'.
Can you help me to learn more?
(Other definitions for pester that I've seen before include "Nag, badger" , "Keep bothering" , "Annoy with persistent requests" , "Annoy with frequent questions" , "Importune" .)