The most common and most likely answer to this crossword clue is the 10 letter word MEANS-TEST
I've seen this crossword clue in The Times
M
E
A
N
S
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T
E
S
T
Buddy explains!
The straight part
We know that "Assess" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case assess = means-test.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 MEANS-TEST mean?
MEANS-TEST verb- To subject a person to a means test, or to require a means test in order to receive a benefit