does it have to be less than 3 per capita? Generally, western restaurants can't get a private room at this price ... If you don't have to have a private room, you can go to Faust (not very authentic French food) or Friday (old American western food, decorated in a cowboy style ~), but Maxim is more expensive, but two people may not be able to let go of the order, so it's better to go cheaper so that you won't lose face with your girlfriend.
Finally, you can try Taiwan Province's Siti Thick Steak, which is cooked in western food. The steak is well-done and won't scare people who eat it for the first time. Besides, the decoration and service are good and it is quite suitable for couples.