This will tell her you’re not only interested in your looks, but interested in her opinion and in looking great together as a couple. If she doesn’t like to dress up, try to find a style which is close to hers, without imitating it. As they like to dress up (see point above), they also want to know they’ve impressed you, and potentially everyone else to.
Ideally, you should really be impressed, and tell the truth when complimenting her. Romanians have a tendency to see conspiracies around them sometimes, so if the compliment sounds too good, or fake, she will figure it out quite rapidly, and add another negative point to your book.
But if you want to impress, and if you want to better integrate and learn your way around Romania anyway, start learning the language.
Take some classes, or even better, ask the woman you like if she wants to teach you some of the basics, and offer to teach her the basics of your language too.
In general, from a practical point of view, foreigners don’t need to learn Romanian as they will get along just fine by speaking English.
But in general, appearance is important for Romanian women, and many like to have impeccable outfits.
So better make sure you try to match her style, or at least avoid being in a totally different ballpark than her.
This will be a great foundation for what you’re trying to build.
If you’ve been in Romania for a while, you probably already know most Romanian women like to dress up for many occasions, and the level of ‘dressing up’ varies with the occasion, and of course, with the woman’s personality.