It is as impossible to find a perfect man as it is to find 100 percent pure gold.

解释 ( paraphrase )
人里面没有完美无缺的人，金子里面没有十足的纯金。
这条谚语告诉我们：人不可能没有一点缺点或错误，不能要求一个人十全十美，只要能够发扬优点，克服缺点就好了。

This proverb cautions us that it is foolish to demand perfection. What we should do is concentrate on developing our merits and overcoming out shortcomings.

足赤：成色十足的金子。
         100 percent pure gold.

赤：纯金。
      Referring to pure gold.

同义词 ( synonym )
白璧微瑕

造句 ( example )
这果然应了那句老话：“人无完人，金无足赤”，看他平常那么和气，发起火来却那么暴躁。