真伪

zhēn wěi nán biàn

真伪难辨

difficult to distinguish between true and false

jiǎn yàn tā chén shù de zhēn wěi

检验他陈述的真伪

test the truth or falsehood of her claims

zhè fú huà de zhēn wěi wú fǎ jiàn bié

这幅画的真伪无法鉴别。

There's no proof about the provenance of the painting.