Let me think about that boy, briefly, in Italian region (6)
I believe the answer is:
umbria
'italian region' is the definition.
(Umbria is an example)
'let me think about that boy briefly' is the wordplay.
'let me think about that' becomes 'um' (expression of hesitation).
'boy' becomes 'brian'.
'briefly' means to remove the last letter.
'brian' with its final letter removed is 'bria'.
'um'+'bria'='UMBRIA'
'in' is the link.
(Other definitions for umbria that I've seen before include "in the Tiber region" , "part of Italy" , "Mountainous region in central Italy" , "hilly area of Italy" , "Italian region" .)