The Frog Princess by E.D. Baker
Princess Emeralda a.k.a. Emma isn’t exactly an ideal princess. Her laugh is more like a donkey’s bray than tinkling bells, she trips over her own feet and she does not like Prince Jorge, whom her mother hopes she will marry. But if Emma ever thought to escape her troubles, she never expected it to happen by turning into a frog! When convinced to kiss a frog so he might return to being a prince, somehow the spell is reversed and Emma turns into a frog herself! Thus begins their adventure-a quest to return to human form.