say you're with your wife/girlfriend/significant other/main squeeze/whatever.
both of you see another woman.
when your wife/girlfriend/etc asks you, "do you think she's pretty?" she wants to know if you want to fuck her seven ways 'til sunday.
it's best to say no and mention exaggerate any small imperfections she may have.
if you say yes, you add the other woman is probably frigid or a lesbian.