The true figure is in this region (5)
I believe the answer is:
realm
'this region' is the definition.
(I've seen this before)
'the true figure is in' is the wordplay.
'the true' becomes 'ream' (I can't explain this - if you can you should give a lot more credence to this answer).
'figure' becomes 'l' (I've seen this in other clues).
'is in' is an insertion indicator.
'ream' placed around 'l' is 'REALM'.
Can you help me to learn more?
(Other definitions for realm that I've seen before include "Kingdom could be lamer" , "Land under a king or queen" , "Empire - state" , "Kingdom, or field of activity" , "Kingdom's" .)