Study source of ceremonies in native American belief (8)
I believe the answer is:
credence
'belief' is the definition.
(I've seen this before)
'study source of ceremonies in native american' is the wordplay.
'study' becomes 'den' (I've seen this before).
'source of' suggests taking the first letters.
'in' indicates putting letters inside.
'native american' becomes 'cree' (an indigenous people of North America).
The initial letter of 'ceremonies' is 'c'.
'den'+'c'='denc'
'denc' going within 'cree' is 'CREDENCE'.
(Other definitions for credence that I've seen before include "Belief; type of table" , "Side table; belief" , "Trust" , "Sort of table" , "Plausibility" .)