The most common and most likely answer to this crossword clue is the 3 plus 3 plus 4 letter word TIE THE KNOT
I've seen this crossword clue in The Daily Telegraph
T
I
E
T
H
E
K
N
O
T
More clues leading to the result TIE THE KNOT
- Thus connect painter with craft and establish union?
- Way to acquire a granny, perhaps, or in-laws?
- Make Union pay church to accept introduction of economic strike in recession
- Hitch up and hike to Barking with tent
- Make granny form a union?
- Marry ultimately perfect man in Windsor, for example?
- Take the plunge and hike to Barking with tent
- Make a granny get married
- . Fasten article on Turk's head, say, to get married
Buddy explains!

The straight part
We know that "get married" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case get married = tie the knot.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.