Evoking happy feelings mixed with sadness (11)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
bittersweet
(Other definitions for bittersweet that I've seen before include "Arousing pleasure tinged with sadness" , "Evoking both pleasure and pain" , "Arousing pleasure tinged with pain" , "Giving both pleasure and pain" , "Pleasant but also painful" .)