Trouble prince experienced at first assimilating directions (6)
I believe the answer is:
hassle
'trouble' is the definition.
(I know that trouble can be written as hassle)
'prince experienced at first assimilating directions' is the wordplay.
'prince' becomes 'hal' (Shakespearean nickname of Henry V when a prince).
'at first' says to take the initial letters.
'assimilating' means one lot of letters goes inside another.
'directions' becomes 'ss' (the abbreviation for south written twice).
The initial letter of 'experienced' is 'e'.
'hal'+'e'='hale'
'hale' placed around 'ss' is 'HASSLE'.
(Other definitions for hassle that I've seen before include "Informal annoyance or quarrel" , "Informally, annoy or harass" , "Irritating inconvenience" , "Pester (colloq.)" , "badger" .)