扮你知己
[bàn nĭ zhī jĭ]
In Chinese culture, '知己' means 'bosom friend', someone you can talk to heart-to-heart without any guard. '扮演你的知己'(Ban Ni Zhi Ji), which literally means 'To Be Your Bosom Friend', usually describes oneself as a close and trustworthy friend who will accompany and support others.