If you want to treat someone to a romantic dinner while in Vegas, we recommend a visit to Lago. This Italian small-bites restaurant inside the Bellagio offers amazing food and views of the Bellagio fountain that are second to none.
The menu is large and offers both vegan and vegetarian options. There are many appetizers -many are less than $15. Some of the classic Italian entrees include the stuffed chicken pomodoro, wild mushroom risotto, Mediterranean salmon, penne, scallops, and many more.
The entrees average around $25+ a dish. Portions are smaller than you might expect at an Italian restaurant- remember, this is a "small bites" spot. A dinner for two will easily cost $100 or more. But, if you can get a seat overlooking the fountain, the view itself is worth the cost of the food.
A little word of warning; the place can get busy and the service may be slow. Spend the time connecting with your date and relishing the ambiance.