Be told how Leonard hid a warm heart (5)
I believe the answer is:
learn
'be' is the definition.
Although both the answer and definition are verbs in their base form, I cannot see how they can define each other.
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for learn that I've seen before include "Be educated" , "Renal (anag)" , "Study or digest" , "Comprehend" , "be taught a lesson" .)