Suit forever? (8)
I believe the answer is:
diamonds
'suit forever?' is the definition.
'diamonds' can be an answer for 'suit' (I've seen this before). I am unsure of the 'forever?' bit.
'suit forever?' is the wordplay.
'suit' becomes 'diamond'.
'forever?' becomes 's' (I can't justify this - if you can you should give a lot more credence to this answer).
'diamond'+'s'='DIAMONDS'
Can you help me to learn more?
(Other definitions for diamonds that I've seen before include "Musically, they're a girl's best friend" , "Very hard, very expensive gems" , "Pieces of the hardest known mineral" , "Pieces of crystalline carbon valued as gems" , "Quarter-deck" .)