All suspicious about nothing, end of story true (5)
I believe the answer is:
loyal
'true' is the definition.
(I've seen this before)
'all suspicious about nothing end of story' is the wordplay.
'all suspicious about nothing' becomes 'loy' (I can't justify this - if you can you should believe this answer much more).
'end of' says to hollow out the word (remove centre letters) (I've seen 'ends' mean this).
'story' becomes 'antinovel' (I have seen 'Unconventional story' mean 'antinovel' so perhaps 'story' could also mean 'antinovel').
'antinovel' with its centre taken out is 'al'.
'loy'+'al'='LOYAL'
Can you help me to learn more?
(Other definitions for loyal that I've seen before include "True to one's allegiance" , "Showing enduring firm support" , "Trustworthy" , "firm in solidarity" , "Not perfidious" .)