/jp/ - Otaku Culture

Yes, the sentence "彼女はプリンセスような美しい。" is incorrect because the noun "プリンセス" (princess) should be followed by the possessive particle "の" (no) when it is being used to modify the adjective "美しい" (utsukushii, beautiful).

The correct way to use the auxiliary verb "ような" to describe the subject "彼女" (kanojo, she) as a beautiful princess would be to add the possessive particle "の" after the noun "プリンセス":

彼女はプリンセスのような美しい人です。 (She is a beautiful person like a princess.)

Alternatively, the sentence could be written using the auxiliary verb "そうな" to describe the subject "彼女" as a princess who appears to be beautiful:

彼女はプリンセスそうな美しい人です。 (She is a beautiful person who appears to be a princess.)