Reversing begins to get one in difficulties (7)
I believe the answer is:
straits
'difficulties' is the definition.
(I've seen this in another clue)
'reversing begins to get one in' is the wordplay.
'reversing' is a reversal indicator.
'begins' becomes 'sts' (I've seen this in another clue).
'to get one' becomes 'tiar' (I can't explain this - if you can you should give a lot more credence to this answer).
'in' means one lot of letters goes inside another.
'sts' enclosing 'tiar' is 'stiarts'.
'stiarts' reversed gives 'STRAITS'.
Can you help me to learn more?
(Other definitions for straits that I've seen before include "Narrow channels of the sea joining two larger bodies of water" , "Dire --, rock band" , "... of Magellan, Hormuz" , "Sea passages" , "Difficulties" .)