Sentimental and so very soft at the story’s end (5)
I believe the answer is:
soppy
'sentimental' is the definition.
(I've seen this before)
'so very soft at the story's end' is the wordplay.
'very soft' becomes 'pp'.
'at' means one lot of letters go next to another.
'end' suggests the final letters.
The final letter of 'story' is 'y'.
'so'+'pp'+'y'='SOPPY'
'and' acts as a link.
(Other definitions for soppy that I've seen before include "Overly sentimental" , "Mawkish" , "Mushy" , "Drenched" , "Silly" .)