汝非柠檬怎知柠檬不萌汝非芒果怎知芒果不盲
[rŭ fēi níng méng zĕn zhī níng méng bù méng rŭ fēi máng guŏ zĕn zhī máng guŏ bù máng]
A playful expression using wordplay, it roughly means 'If you're not a lemon, how would you know if a lemon is not cute? If you're not a mango, how would you know if a mango is not blind?' It humorously refers to not understanding someone or something unless experienced personally.