Niste:

I was in Nepal two months ago and had my H1b visa stamped. They did ask me the same thing for if I had any marriage plans and I said may be . Out of curiousity I asked the consular why she needed that information and she replied that most of the people apply as single for H1b visa stamping and after few days the bride will come as the dependent so it seemed fishy.

Your girl friend can travel to US on tourist visa but chances for a Nepalese resident to receive a tourist visa is slim. But if she will be able to come to US then you can get married to her here in US and request for her visa change with USCIS.

So here are your options:

1. She can apply for Tourist visa (very low probability )

2. She can apply for F1 visa (good chances provided she is a good student and her papers are strong).

3. You go to Nepal, get married and apply for her H4 visa (very high probability and the best option)

Ciao