Succeeded in real estate, securing one affluence (10)
I believe the answer is:
prosperity
'affluence' is the definition.
(thesaurus)
'succeeded in real estate securing one' is the wordplay.
'succeeded' becomes 's' (genealogical abbreviation).
'in' indicates putting letters inside.
'real estate' becomes 'property' (I've seen this before**).
'securing' is an insertion indicator.
'one' becomes 'i' (Roman numeral).
's' placed inside 'property' is 'prosperty'.
'prosperty' enclosing 'i' is 'PROSPERITY'.
(Other definitions for prosperity that I've seen before include "Things going well" , "Financial success" , "wealth" .)