我羡慕别人的她
[wŏ xiàn mù bié rén de tā]
It literally means 'I envy her.' Here, 'her' might refer to any enviable women. In real life, everyone has some traits worth learning from. One aspect that many are envious of others is their happiness in romance. So, this username conveys a mix of jealousy, admiration, and possibly loneliness.