Promotes English model, svelte, full of charm at heart (8)
I believe the answer is:
elevates
'promotes' is the definition.
('elevate' can be a synonym of 'promote')
'english model svelte full of charm at heart' is the wordplay.
'english' becomes 'e' (abbreviation).
'model' is an anagram indicator.
'full of' is an insertion indicator.
'at heart' means to look at the middle letters.
The centre of 'charm' is 'a'.
'svelte' anagrammed gives 'levtes'.
'levtes' placed around 'a' is 'levates'.
'e'+'levates'='ELEVATES'
(Other definitions for elevates that I've seen before include "Lifts or raises to higher position" , "Raise from lower to higher position" .)