口说无凭

kǒu shuō wú píng lì cǐ wéi jù

口说无凭，立此为据。

Verbal statements being no guarantee, a written agreement is hereby made.

kǒu shuō wú píng wǒ men yòng xíng dòng zhèng míng

口说无凭，我们用行动证明！

Acts speak louder than words!