Gifted, but finish with nothing and get married (7)
'gifted' is the definition.
(endowing is a kind of gifting)
'finish with nothing and get married' is the wordplay.
'finish' becomes 'end' ('end' can be a synonym of 'finish').
'with nothing' becomes 'o' (I've seen this in other clues).
'and' means one lot of letters go next to another.
'get married' becomes 'wed' ('wed' can be a synonym of 'get married').
'but' acts as a link.
(Other definitions for endowed that I've seen before include "Bequeathed income to", "Invested", "Provided with permanent income or ability", "Given a permanent income", "given a portion?".)