Answer:
Sting is awake; Fiona is awake
Step-by-step explanation:
Since everything they believe while awake is true, both Sting and fiona are awake because Sting believes that Fiona believes that he is asleep, and Fiona believes that Sting is asleep: they just believe , in other words, they think those situations are true, correct, or real -- they don't dream about them -- so they are awake.