The most common and most likely answer to this crossword clue is the 10 letter word RING-FENCE
I've seen this crossword clue in The Guardian
R
I
N
G
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F
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E
More clues leading to the result RING-FENCE
- Call on crook to guarantee funds won’t be misused
- Call criminal dealer to provide financial protection
- Thief with hot goods may do this to keep within bounds
- Enclose phone receiver
- To guarantee money for a specific purpose call receiver
- Assign funds solely for telephone receiver
- Group with criminal to reserve funds?
- Protect re-enforcing order or be ignored
- 28a
Buddy explains!

The straight part
We know that "Assign funds solely for/Assign funds solely for" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case assign funds solely for/assign funds solely for = ring-fence.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 RING-FENCE mean?
RING-FENCE verb- To guarantee the safety of funds or investment. In particular, to ensure some degree of distinction for monies, that may provide immunity against untoward financial claims.
- To specify that funds may only be used for a specific purpose, especially government funds.
- To require workers to remain in (particular types of work), as during wartime.