A Mrs barges in violently — it's hard to deal with (12)
I believe the answer is:
embarrassing
'hard to deal with' is the definition.
(something embarrassing is difficult to deal with)
'a mrs barges in violently' is the wordplay.
'violently' is an anagram indicator.
'a'+'mrs'+'barges'+'in'='amrsbargesin'
'amrsbargesin' with letters rearranged gives 'EMBARRASSING'.
'it's' is the link.
(Other definitions for embarrassing that I've seen before include "Causing one to feel awkward" , "Socially very awkward" , "Ticklish" , "Causing to feel shame" , "Humiliating" .)