Thailand? I'm confident it's mainly Buddhist (5)

I believe the answer is:

tibet

'it's mainly buddhist' is the definition.
(Buddhism is the main religion in Tibet)

'thailand? i'm confident' is the wordplay.
'thailand?' becomes 'T' (abbreviation on car registration plates).
'i'm confident' becomes 'I bet' ('I bet that...').
't'+'ibet'='TIBET'

(Other definitions for tibet that I've seen before include "far-flung highland area" , "Asian location" , "Home country of the Dalai Lama (5)" , "hilly region" , "Land of the Dalai Lama" .)

I've seen this clue in The Guardian.

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