姐姐不花心妹妹不挑心
[jiĕ jiĕ bù huā xīn mèi mèi bù tiăo xīn]
'Elder Sister Is Not Flirtatious, Younger Sister Doesn’t Choose Fussy' highlights familial relationships: The older sister isn’t capricious in romance, while younger sisters often are expected to be innocent without too much romantic fuss.