Mean in the end, he must leave (6)
I believe the answer is:
intend
'mean' is the definition.
(to intend to something is to mean it)
'in the end he must leave' is the wordplay.
'must leave' indicates named letters should be taken away.
'the'+'end'='theend'
'theend' with 'he' removed is 'tend'.
'in'+'tend'='INTEND'
(Other definitions for intend that I've seen before include "1 dn [DESIGN]" , "Tinned (anag.)" , "Have as purpose or in mind" , "Mean - purpose" , "Mean; aim" .)