There's a reason Cissie bestows fun nicknames on Fuu: she honestly thinks Fuu's a great person. Very weird (thanks to the differences in their cultures and worlds), but fun to hang out with nevertheless! And very smart too-- Fuu could probably give Cissie's genius friend a run for his money.

Either way, Cissie likes Fuu a lot and hopes that they can continue to be good friends. ♥