The princess isn't ugly. She is young.
Explanation
The following test is for students who are in 6 Year. Its purpose is to check the students' knowledge of the adjectives of appearance.
The Santa Claus can't be wavy. He isn't slim.
She hasn't got straight hair. Hair can't be big.
She's got black hair, not brown. Her hair isn't short.
He is slim. He isn't tall.
It isn't new. We can't say that a car is plump.
The monster isn't slim. It isn't beautiful. It is short, not tall.
His hair isn't long. Hair can't be fat.
The cat hasn't got small eyes. Eyes can't be straight.
He's got short hair, not long. His hair is straight, not wavy.