[ Well she has feelings for the "spirit" of King Arthur, who by the way is a chick and is going through a goth phase. So there's that. ]

Only about what I've read in tales before coming here which means there remains a chance what I do know is dated.

--but mermaids are very deadly as well as possessive. You'll want to be charming, but not too charming. After all, if she happens to like you enough, she'll try to bring you into the water with her.

... by the way, it should go without saying, but don't get in the water around them.