The first rule of fight club is you do not talk about fight club. The second rule of fight club is you do not talk about fight club.
The same rule applies when any woman asks you how they look. You do not talk about nuthin'. Shut your mouth. Keep your opinions to yourself. Resist the urge. Because anything you say, no matter how good it sounds in your head will never be good enough. If you must give an answer, mumble. If she must hear your thoughts, one word answers will do. If she needs to know and has blocked off all emergency exits, well you're fucked.
Or you can show her this.
And maybe for once, it is she who will be the one left speechless.