Stimulate love for what's silent in autumn, sweetheart? (6)
I believe the answer is:
endear
'stimulate love' is the definition.
'what's silent in autumn sweetheart?' is the wordplay.
'what's silent in autumn' becomes 'en' (I can't justify this - if you can you should believe this answer much more).
'sweetheart?' becomes 'dear' (both are terms of address to romantic partner).
'en'+'dear'='ENDEAR'
'for' is the link.
Can you help me to learn more?
(Other definitions for endear that I've seen before include "Make love" , "Earned (anag.)" , "Make beloved" , "Make attractive or lovable" , "Attract" .)