Well-heeled demi-mondaine provides American capital (8)
I believe the answer is:
richmond
'american capital' is the definition.
(state capital of Virginia)
'well-heeled demi-mondaine' is the wordplay.
I cannot quite see how this works, but
'well-heeled' could be 'rich' (similar in meaning) and 'rich' is located in the answer.
This explanation may well be incorrect...
'provides' acts as a link.
Can you help me to learn more?
(Other definitions for richmond that I've seen before include "Sweet lass of - Hill" , "Yorkshire town close to Catterick garrison" , "Thames-side town" , "Capital of Virginia, USA" , "Just copes" .)