I can just imagine, Astrogirl misheard the person on the telephone and in fact was being asked if they wanted a room where they could have a window over the Bundt cake factory!
The 2nd poster is correct. The Bund is the waterfront main road in Shanghai (relic of the time when Shanghai was dominated by Westerners). And a Bund view room is simply a room with a view of it.
As per other posters, the river’s not named Bund; the waterfront is.
Something to be aware of, if this matters to your reservation: the Bund itself is old and relatively low-rise. There is at least one old, charming hotel (the Peace Hotel) on it. I suggest grabbing a drink in the hotel bar to feel like you’ve stepped into an Indiana Jones movie.
Most likely, though, “Bund view” means ACROSS the river in one of the 850-story new hotel / office complex towers, which will provide a nice view of the Bund through binoculars.