Of course, you have to always look outside the box. Life is a riddle and even if answers are given to you the solution isn't always as simple as A, B, and C.
Sane Intelligent in this case is basically (since I see life as a game, lets say this is a character select screen) a beginners class. A jack of all trades and basically the closest thing to the perfect woman. A sane intelligent woman knows that she will never attain a perfect beauty but she knows how to work around it. She knows what sort of personality attracts men and in her own way she can be just as enticing as a beautiful sane girl. She has the highest chances on being faithful to her mate. This is because she knows what she wants.
A Beautiful sane girl is the ranger of the litter. She has one of the highest chances of cheating on her mate. She knows she's beautiful, she knows she could have whoever she desires (somewhat). She doesn't need to work around her appearance and her self confidence is almost maxed out. She has the highest chances on being unattractive when she gets older as well. You know what they say about bright stars.
Beautiful intelligent girl is basically the type that'd cut of your penis. She's smart but she doesn't have all her eggs in a row. She may be faithful, but she may be a little too faithful. If you even smile at a girl wrong, tough break man.. tough break.