Causing deep distress, inquiry involving tide (5-7)
I believe the answer is:
heart-rending
'causing deep distress' is the definition.
I can't judge whether this defines the answer.
'inquiry involving tide' is the wordplay.
'inquiry' becomes 'hearing' (hearing is a kind of inquiry).
'involving' means one lot of letters goes inside another.
'tide' becomes 'trend' (I can't explain this - if you can you should give a lot more credence to this answer).
'hearing' going around 'trend' is 'HEART-RENDING'.
Can you help me to learn more?
(Other definitions for heart-rending that I've seen before include "Causing great sadness or distress" , "Greatly distressing" , "moving" , "Poignant" , "Agonisingly sad" .)