The most common and most likely answer to this crossword clue is the 6 letter word REALLY
I've seen this crossword clue in The Times
R
E
A
L
L
Y
More clues leading to the result REALLY
- Recover after injection of illegal drug? Come off it!
- Friend follows soldiers, in truth.
- In truth referring to supporter
- You don't say upturn has to save energy
- So, are you convinced?
- Join forces again, in fact
- A pound in the bank; are you sure?
- So concerned with partner
- Band together once more? No kidding
- Very concerned with partner
Buddy explains!
The straight part
We know that "are you sure?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case are you sure? = really.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 REALLY mean?
REALLY adverb- In a way or manner that is real, not unreal.
- (modal) Actually; in fact; in reality.
- (as an intensifier) Very (modifying an adjective); very much (modifying a verb).
- Indicating surprise at, or requesting confirmation of, some new information; to express skepticism.
- (sarcastic, typically exaggerated question.) Indicating that what was just said was obvious and unnecessary; contrived incredulity
- Indicating affirmation, agreement.
- Indicating displeasure at another person's behaviour or statement.
- To bring together again.
- To ally anew; to re-form an alliance.