是我三生有幸能喜欢你是我三生有幸被你回应
[shì wŏ sān shēng yŏu xìng néng xĭ huān nĭ shì wŏ sān shēng yŏu xìng bèi nĭ huí yīng]
This translates to 'It is my great fortune from previous lives to love you, it is my destiny to be responded by you', indicating deep appreciation and feeling lucky for receiving someone's affection back in return.