毕竟你那么开心而你也没有难过
[bì jìng nĭ nèi me kāi xīn ér nĭ yĕ méi yŏu nán guò]
'After all, you were so happy, and you weren't sad.' It may imply a contrast where one's happiness is emphasized yet it subtly mentions the other side - a kind of solitude because there might be no sadness either, hinting at detachment from feelings. Possibly suggests being content with another person's joy and accepting of oneself's lack thereof.