It's sweeter when in difficulties knowing how to handle oneself (10)
I believe the answer is:
streetwise
'in difficulties knowing how to handle oneself' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'it's sweeter' is the wordplay.
'it's sweeter' can be anagrammed to 'STREETWISE'.
Though, I am not sure how the anagram is indicated.
'when' is the link.
Can you help me to learn more?
(Other definitions for streetwise that I've seen before include "Experienced in urban life" , "Experienced in harsh city life" , "With urban savoir-faire" , "Well adapted to urban life" , "like your London cabbie, no doubt" .)