Succeeded in real estate, securing one affluence (10)
I believe the answer is:
Here is my best explanation:
'affluence' is the definition.
'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 "Financial success", "Things going well", "wealth" and "Wealth".)