The most common and most likely answer to this crossword clue is the 10 letter word DIFFICULTY
I've seen this crossword clue in The Times
D
I
F
F
I
C
U
L
T
Y
Buddy explains!

The straight part
We know that "trouble" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case trouble = difficulty.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 DIFFICULTY mean?
DIFFICULTY noun- The state of being difficult, or hard to do.
- An obstacle that hinders achievement of a goal.
- (sometimes in the plural) Physical danger from the environment, especially with risk of drowning
- An objection.
- That which cannot be easily understood or believed.
- An awkward situation or quarrel.