Kaoru decides to team up with some powerful people she can trust to help her share the benefits of her potions with even more people. But just as her new business is underway, an unexpected visitor comes looking for her...
I think you're going for "flat chest."
"أعتقد يمكن اعتماد "الصّدر المُسطّح
Dann lieber „flat chest“.
"Tabla de planchar" la representa más.
"Tabla de planchar" la representa más.
Ou « au buste plat », sinon ?
Allora, perché non "flat chest"?
Nesse caso, deveria ser 
"Flat Chest", não acha?
А я должен буду ответить «плоская грудь».