Do you guys have a mutual girl friend? Maybe you could tell the mutual friend that “I really like her, but her lipstick color is too bright for me. What do you think?” Depending on her reaction, maybe you could gauge your almost girlfriend’s reaction. If she agrees with you, maybe you could tell the mutual friend “could you possibly hint around about how her lipstick is too red? Maybe help her shop for a more flattering shade?”
Or if you can stand the lipstick shade enough to go into a deeper relationship with this intelligent and attractive-in-all-other-ways woman…when you kiss most or all of it off of her and she says “oh, I have to go refresh my lipstick”, you could say “oh, don’t do that. I love the ‘i just kissed the hell out of you’ look. It’s so sexy.” And if she keeps saying “but i have to put something on my lips” you could say “you know, some I betcha some tinted lipgloss or a paler shade would look soooo good on you”.
But, then again, that sounds kinda gay.
Hell, I don’t know. I’m not a guy, I don’t know how to tell a girl that her lipstick shade is too red!!! As a girl, I would tell another girl (and only if I knew her well enough to know she can take some criticism and can appreciate it, and hopefully give ME constructive criticism when I need it) “honey, your lipstick is too damn red. Blot it or something. Here, try this shade…”