Following sentence shows hoped-for future (9)
I believe the answer is:
afterlife
'hoped-for future' is the definition.
(I've seen this before)
'following sentence' is the wordplay.
'following' becomes 'after' (I've seen this before).
'sentence' becomes 'life' (I have seen 'Longest sentence' mean 'life' so perhaps 'sentence' could also mean 'life').
'after'+'life'='AFTERLIFE'
'shows' is the link.
(Other definitions for afterlife that I've seen before include "Existence following death" , "Post-death existence" , "paradise" , "Existence beyond the grave" , "Hoped-for future" .)