This is not a fairytale and there are no happy endings here.
In another life she would be wiser, she would be more courageous and she would tell him the truth right at the beginning, right then, when he first stepped inside her sad, little world, suddenly filling it with his charm and humor. She'd let him see her feet and maybe he wouldn't fall for her; maybe he would just let her do her job and then leave, never come back, never causing so much heartbreak and pain.
Or maybe- just maybe- he wouldn't.
Maybe this thing which was between them would be different. More honest. Maybe she wouldn't be so scared. Maybe he would take things slower, be more careful, didn't let himself fall so quickly and so hard. Maybe things would be easier.
In another life, Luna wouldn't mess up with Earth and Kai's father would live and rule for many years. In another life Peony wouldn't die; she would take the cure on the right time and live happily ever after.
Maybe Cinder would be able to give Iko the body she deserved and craved for so much. Delicate, femine body, with small feet to wear beautiful shoes on them and soft locks and bright, big eyes.
In another life Cinder might get her happy ending; might get a handsome price who doesn't care that she's only partially human, she might get a place to call home, the person to call her home. She might, for the first time in forever, finally be enough for somebody.
She can imagine her wedding, her white, silk gown and long veil holded by Peony and Kai's smile and her own laugh and life filled with joy and happiness along with her sister, her friend and men she fell hopelessly for. A life in which she could be sure of what and who she is, surrounded by love of her loved ones. No worries about her Lunar blood. Without worries about her true identity. Without Adri, without Lavinia and without bitter taste of regret, without the image of disgust in Kai's eyes when he saw her mechanical feet.
But her life wasn't a fairytale and maybe she was a princess, but not a happy one. And there were no happy endings.
Only bitter endings and ashes, ashes all around her.