I love it as a middle name. I've always been fond of it after reading The Count of
Monte Cristo eons ago. (
Valentine was a tertiary character).
I love:
Alice ValentineClare ValentineRose Valentine
But that's probably because I tend towards "boring" old-fashioned names.
As far as a feminine but strong name, the way you've described
Valentine, I've always thought of
Justine.