My wife went bananas when I tried Mughetto di Bologna from Razorock. It's Lily of the Valley scented. I personally don't use it after one try, but I ended up getting a custom brush (AceByTerror) made for her.
I would get her a bunch of samples from MysticWaters or Mike'sNaturals. The price & shipping is right & I find those soft samples and generous sizes a bit easier to use than my slippery MamaBear samples (who also have a great scent selection). As a female soap junkie, I love being able to pick a scent & formula depending on my mood. As others have mentioned, there's no gender to fragrance & she may end up loving something woodsy or earthy. Let her sniff some of your collection to get ideas (Some of my favorites are hand-me-downs from my BF)