The most common and most likely answer to this crossword clue is the 11 letter word CROSS-CHECK
I've seen this crossword clue in The Guardian
C
R
O
S
S
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C
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Buddy explains!
The straight part
We know that "Make sure that’s right" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case make sure that’s right = cross-check.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.
Crossword Answer definitions
CROSS-CHECK verb- To verify (data or calculations) by using an alternative source or method.
- To commit the infraction of checking an opponent by using the shaft of one's stick with both hands.