A girl who enters shidduch age may put on makeup and wash her hair even while she's sitting shiva, so the boys should run after her (Tainis 13b). In other words, if people see her ugly a bad name will go out on her. Many girls have this krenk that "he should love me as I am". (Click Mar 27, 2011)
I once went out with a girl who had a mole on her arm, and a big black hair came out of it. Now you tell me, if she can't cut one hair for you what will she yes do for you? You might as well marry a dog.