你从没见过我一个人时孤独
[nĭ cóng méi jiàn guò wŏ yī gè rén shí gū dú]
Translates to 'you've never seen my loneliness when I'm alone.' This expresses the private struggles or inner emotions kept hidden from the world around, indicating that even solitude doesn't equate with true loneliness unless deeply felt.