Hmmm talk about being caught between a rock and a hard place.
Mrs F obviously thought that she looked good, and if you think you look good then you feel great along with it.
However think I'd rather know if something didn't suit me, so I'd go with telling her and being 100% honest.
It does depend on your relationship. But I would guess that she would much rather you were honest than said you liked something when your body language will be sending deafening messages to the contrary.
If she does wear it again you won't be relaxed with her anyway.
I know that some colurs make me look dead and aothers make me look good. If you get into the conversation, best plan is to focus on the positives rather than simply say it doesn't suit her.
Maybe you could, next time you are out together, notice someone wearing a dress or colour you know would suit her and then mention that the dress she had on before didn't compliment her hair, bring out her natural glow (whatever was the problem in the ifrst place).
be honest about it ,although it may cost you a new dress.
