Really marvellous blankets back in hotel providing comfort (6)
I believe the answer is:
solace
'comfort' is the definition.
(I know that comfort can be written as solace)
'really marvellous blankets back in hotel' is the wordplay.
'really' becomes 'so' (both can mean 'extremely').
'marvellous' becomes 'ace' (I can't justify this - if you can you should give a lot more credence to this answer).
'blankets' indicates putting letters inside (I've seen this in other clues).
'back in' says to take the final letters (the 'back' of the word).
The final letter of 'hotel' is 'l'.
'so'+'ace'='soace'
'soace' enclosing 'l' is 'SOLACE'.
'providing' is the link.
Can you help me to learn more?
(Other definitions for solace that I've seen before include "Comfort in misery" , "console" , "amusement" , "Consolation, comfort" , "Relief in affliction" .)