Symbolism, Imagery, Allegory
It wouldn't be "Cinderella" without shoes. Hey, we even get glass slippers. While Ella and Char are exploring the old royal castle, they find an abandoned room with a pair of unbreakable glass slippers inside. (We know they're unbreakable because Ella drops them, since she's kinda clumsy, and they survive.)
In a twist on other versions of the "Cinderella" story, though, it's not the glass slipper that IDs her after the ball. When Ella's unmasked, Char knows who she is and where to find her. Instead, he uses the "let's have the maidens in the house try on the slipper" ploy to gain entry, since if Dame Olga and Hattie knew he was there for Ella, they could order Ella to stay hidden or something like that. Well, maybe Char doesn't think of it like that since he doesn't know about the obedience spell, but his prior attempts to visit Ella at home failed, so that might be why he has a better plan this time.
In other words, Char uses the traditional fairy-tale and puts a twist on it—just like this book does. So, on the one hand, the shoes are a symbol of this classic tale's twists and turns.
Feet Are the Window to Your Soul
But the story also goes a little traditional, making it so that tiny, pretty, non-stinky feet point to a small, pretty, non-stinky girl.
When Char shows up with the slipper, Hattie claims it as her own, saying: "It's been missing for years." (29.29) Both her feet and Olive's are much too large. Hattie has the additional characteristic of having really stinky feet, something that Ella knows all too well from all the times Hattie has ordered her to remove her slippers.
Ella's feet are tiny enough for the slippers because of Ella's fairy blood. Since the slippers were found inside a dusty old workbench, it's probable that they belonged to someone who had lived and died long ago. Was it a fairy, or someone with fairy blood like in Ella's mother's line? The mystery is never explained. Regardless, knowing about people's feet can give you insight into their character, such as identifying fairies through their tiny feet.
We're not saying that having huge, stinky feet like Hattie does makes you a bad person, but, well, personal hygiene is never a bad thing.
Do the Twist … Again
But here's the thing: it doesn't seem like Char ever really cares that Ella has small feet. (Small feel have been a traditional sign of beauty in lots of cultures.) Since it's not like he needs the slipper to find out who she is, the size of her feet is irrelevant to him. He's already fallen in love with her because of her sexy, sexy brain. That's not something we see in most other versions of "Cinderella"—or Shakespeare—where apparently you can dance with someone at a ball for like half an hour and totally fall in love.
Sure, Ella and Char dance. When they first discover the shoes and Ella puts them on, they dance to music overheard from Sir Peter and Dame Olga's wedding. Thanks to Ella's time at finishing school, she can manage to not trip over her own feet, and so she and Char can talk and flirt while dancing. How do we know it's flirting? Ella says: "He put his hand on my waist, and my heart began to pound, a rougher rhythm than the music. … Our free hands met. His felt warm and comforting and unsettling and bewildering—all at once" (21.68).
So, that sounds a lot like flirting—but they're not in love yet. They're in like, maybe, but love comes later, after lots of letters and lots of time together. Which, if you ask us, is just how it should be.