It's tough to change a woman's mind once it's made up. If I simply "like" a perfume, I wouldn't wear it. If I love it and it's wearable, it will be worn and the fragrance will be a constant reminder of the person who gifted me with it.
She doesn't have too many fragrances in her collection -- I say that it's better to spend much money and have her use the fragrance rather than to spend smaller amount of money and have the bottle sit around unused. If you can, budget in other areas to afford this one purchase.