Frank is one in awful screen production (7)
I believe the answer is:
sincere
'frank' is the definition.
(frank can mean sincere or honest)
'one in awful screen production' is the wordplay.
'one in' is an insertion indicator.
'awful' indicates anagramming the letters.
'production' becomes 'i' (I can't explain this - if you can you should believe this answer much more).
'screen' anagrammed gives 'sncere'.
'sncere' placed around 'i' is 'SINCERE'.
'is' is the link.
Can you help me to learn more?
(Other definitions for sincere that I've seen before include "Showing genuine feelings" , "like informal correspondents?" , "Pure" , "Perfect" , "straightforward" .)