有些玩笑是真的有些真的是玩笑
[yŏu xiē wán xiào shì zhēn de yŏu xiē zhēn de shì wán xiào]
Meaning ‘Some jokes are true and some truths are jokes,’ it indicates an attitude where the user might express truths through joking around and sometimes uses humor to hide deeper meanings or secrets. There's a bit of ambiguity here about seriousness versus jesting.