只肯为你装淑女
[zhĭ kĕn wéi nĭ zhuāng shū nǚ]
With a slightly humorous tone, it means 'Willing to pretend to be ladylike just for you'. This online name might indicate that normally this person is not that proper but would make effort to show a more delicate side only to a specific person out of affection or other reasons.