Rising can be very difficult (6)
I believe the answer is:
uphill
This might be a double definition.
'rising' is the first definition.
(I know that rising can be written as uphill)
'very difficult' is the second definition.
'uphill' can be an answer for 'difficult' (I've seen this in another clue). I am unsure of the 'very' bit.
'can be' acts as a link.
Can you help me to learn more?
(Other definitions for uphill that I've seen before include "Towards the summit" , "Laborious as for walker" , "Ascending -- sort of struggle" , "like the road to the Galibier?" , "This going is tough, but climb on" .)