Daughter forsakes trifling romance for marriage (8)
I believe the answer is:
alliance
'for marriage' is the definition.
(I've seen this before)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for alliance that I've seen before include "League - treaty" , "Federation" , "Combination by treaty" , "Union for mutual benefit" , "Wanting marriage" .)