Do you know what her favorite dish/cuisine is? If not, I'd work it into a conversation, and surprise her. I wanted to plan an elaborate dinner for a friend, and found his favorite was meatloaf and spinach drowned in butter. Saved me lots of time and effort. Not knowing her preferences, here are some suggestions:
Shrimp scampi served over angel hair or spinach fetucinne
(While the water is boiling for the pasta, heat some oil and buttter, saute garlic, add shrooms if you like, toss in the shrimp. Top the pasta with shrimp, shredded fresh Parm, and fresh herbs, if you like -- white wine for a libation, simple salad and dessert, garlic bread, if you wish.)
Linguine and clams or clam sauce.
Penne in vodka/tomato sauce (cream sauce).
Cornish game hens, rice pilaf (there are boxed quick ones), or instant couscous (takes five minutes). Place the hens over rice, surround with mandarin oranges (you can find them in a can). Nice presentation too.
You could carry over the mandarin oranges in a simple salad of baby spinach, red onions, fresh sliced shrooms.
Strawberry shortcakes with whipped cream. You can find prepaackaged shortcake shells near the strawberries in produce section. Fill the cakes with berries and whippped cream. Double stack them for a super-duper look.
Chicken Scalopinne or chicken Marsala, serve with buttered herbed noodles.
Eggplant parmesan & spaghetti with olive oil, garlic and herbs & a crisp green salad.
Stuffed shells - very easy - serve with salad, garlic bread, wine & dessert.
You can also do a search on this site, by keying in a main ingredient, as there are so many excellent recipes here.
If you're pressed for time, there are some pretty good packaged garden salad blends and an array of dressings, add some croutons and shredded cheese of choice, halved cherry tomatoes - whatever you like.
Have a great dinner, and let us know how it turns out.