Desire what church will often support (6)
I believe the answer is:
aspire
'desire' is the definition.
(thesaurus)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for aspire that I've seen before include "Hanker" , "Hope, dream" , "Have hopes (to achieve something)" , "Hope (to achieve)" , "Wish to rise (to)" .)