是骡子是马，牵出来遛遛
shì luó zi shì mǎ , qiān chū lai liù liu
lit. to see whether it's a mule or a horse, take it out for a walk (idiom)
fig. the proof of the pudding is in the eating; to show what one is made of
是
shì
to be (followed by substantives only)
骡
luó
mule
子
zi
noun suffix, as in 椅子[yi3 zi5] "chair"
是
shì
to be (followed by substantives only)
马
mǎ
abbr. for Malaysia 馬來西亞|马来西亚[Ma3 lai2 xi1 ya4]
，
,
牵
qiān
to lead along
出
chū
variant of 出[chu1] (classifier for plays or chapters of classical novels)
来
lai
to come
遛
liù
to stroll
遛
liu
to stroll