Attendace of the US citizen at the interview is "recommended but not required".
I believe it would be a very good thing to go with her if possible. I went with my fiance for his interview (in Ankara, Turkey) and the interviewer asked me many questions as well as him. Going together is probably the best way to prove you have a bona fide relationship. For example, we brought pictures, emails, chat logs, etc., but we were not even asked to show them. I believe this was because we were together and our feelings for each other were obvious.
Also, at his interview, I saw and overheard other people's interviews (the interview was conducted in a large room, similar to a bank lobby and you could hear everything being said). I watched several people who were there alone get turned down for lack of evidence of a bona fide relationship, even after their interview appeared to go well otherwise. I watched other couples who were there together (some of whose interviews appeared to go rather badly) get approved in the end, I believe because the US citizen was there saying, "I love this person and I want them to be with me."
Good Luck,
Tanya
QUOTE (Malla @ Dec 21 2007, 12:28 PM)

hello everyone,
I got aproval letter on Dec 13 from USCIS. Hope NVC will send documnets soon to embessy. I am also going Nepal on Jan 9 for 1 months. Does it make any differnece or negative effect if i aslo go to inteview with my faincee. Should i go or not with her? Need suggestion from you guys. Thanks