The most common and most likely answer to this crossword clue is the 7 letter word BLESSES
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Buddy explains!

The straight part
We know that "Sanctifies" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sanctifies = blesses.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.
What does BLESSES mean?
BLESSES verb- To make something holy by religious rite, sanctify.
- To make the sign of the cross upon, so as to sanctify.
- To invoke divine favor upon.
- To honor as holy, glorify; to extol for excellence.
- To esteem or account happy; to felicitate.
- To wave; to brandish.
- (past tense only blessed) To turn (a reference) into an object.
- (with from) To secure, defend, or prevent from.