Agonising trial involving Vogue (12)
I believe the answer is:
heartrending
'agonising' is the definition.
(I've seen this before)
'trial involving vogue' is the wordplay.
'trial' becomes 'hearing' (as in a court hearing).
'involving' indicates putting letters inside.
'vogue' becomes 'trend' (synonyms).
'hearing' going around 'trend' is 'HEARTRENDING'.
(Other definitions for heartrending that I've seen before include "Tragic" , "Distressing" , "Agonising" , "causing great sadness" .)