I tried and I can't think of a guilty pleasure!!! For guilty pleasures... it's difficult because she's broken free from her shackles of being ishgardian (debuff). I'm not sure there's anything she's guilty about enjoying.

So, I'll do a secret-- some of the scions know, and she definitely doesn't bring it up casually, before she ran away from home she was pretty promiscuous, mostly to use it against people. She does NOT feel bad about this (mostly...) No one who sees her (and manages to recognize her) in HW would dare say a word, because it implicates them, too, lol. Plus, she's completely mellowed out in her mid 20s-30s.
She does keep a lot to herself in general, but I don't think they're secrets. She's just private in general.

I hope these kinds of things were what you were looking for ;w;;