Account starts to concern Rwandan ambassador in African capital (5)
I believe the answer is:
accra
'african capital' is the definition.
(capital of Ghana)
'account starts to concern rwandan ambassador' is the wordplay.
'account' becomes 'ac' (abbreviation for account).
'starts to' says to take the initial letters.
The initial letters of 'concern rwandan ambassador' is 'cra'.
'ac'+'cra'='ACCRA'
'in' is the link.
(Other definitions for accra that I've seen before include "West African capital" , "Ghana's capital" , "Largest city of Ghana" , "Ghanaian capital" , "African city" .)