Красота до вечера, а доброта навек

Marry a kind person rather than a beautiful one. See Красота до венца, а ум до конца (K), Красотой сыт не будешь (K)

Cf: Beauty is only skin-deep (Am., Br.), Beauty is only skin-deep; goodness goes to the bone (Am.). Beauty is skin-deep; it is the size of the heart that counts (Am.). Looks aren't everything (Am.)