Reversing begins to get one in difficulties (7)
I believe the answer is:
straits
'difficulties' is the definition.
(thesaurus)
'reversing begins to get one in' is the wordplay.
'reversing' says the letters should be written in reverse.
'begins' becomes 'starts' ('start' can be a synonym of 'begin').
'to get one' becomes 'i' (I can't justify this - if you can you should give a lot more credence to this answer).
'in' indicates putting letters inside.
'starts' placed around 'i' is 'stiarts'.
'stiarts' in reverse letter order is '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" .)