Koisuru Ouji to Junan no Himegimi

Mira falls off from a tree but before he reached the bottom, Prince Alex saved him! Prince Alex has been searching for his lost love and Mira looks exactly like her! Prince Alex is convinced that Mira is his lost princess, so he insists they take a bath together! However, he is disappointed when it turns out Mira is really a man. But that won't stop Alex from loving him and trying to find out the mysterious past that Mira holds!

(Source: LuffyNoTomo Translations)