Burdened boy with heartache and desperation in the end (5)
I believe the answer is:
laden
'burdened' is the definition.
(synonyms)
'boy with heartache and desperation in the end' is the wordplay.
'boy' becomes 'lad' (informal term for boy).
'with' means one lot of letters go next to another.
'heartache' becomes 'e' (I can't justify this - if you can you should believe this answer much more).
'and' says to put letters next to each other.
'in the end' suggests the final letters.
The final letter of 'desperation' is 'n'.
'lad'+'e'+'n'='LADEN'
Can you help me to learn more?
(Other definitions for laden that I've seen before include "cargo aboard" , "'Burdened, oppressed (5)'" , "fully charged" , "Loaded - oppressed" , "Carrying goods" .)