YOU SAID:

My cat is partying at the duchess' castle.

INTO JAPANESE

私の猫は公爵夫人の城でパーティーをしています。

BACK INTO ENGLISH

My cat is partying at the Duchess's Castle.

INTO JAPANESE

私の猫は公爵夫人の城でパーティーをしています。

BACK INTO ENGLISH

My cat is partying at the Duchess's Castle.