Prove to be clear (4,3)
I believe the answer is:
turn out
This clue might be a double definition.
'prove' is the first definition.
(I know that prove can be written as turn out)
'be clear' is the second definition.
'turn out' can be an answer for 'be' (turning out is a kind of being). I am unsure of the 'clear' bit.
'to' is the link.
Can you help me to learn more?
(Other definitions for turn out that I've seen before include "A number at meeting" , "Eventually appear" , "Prove" , "assembly" , "Eject" .)