I don't know that I would respond to it. Afterall, what would you say that she hasn't heard already? Even if you had something new, do you really think it would be heard?
I think the "let's be friends" $hit is their way of defining what you won't be. Like alot of folks here, I got that too.
Are my H and I friends? Will we be? I don't know. I subscribe more to the thinking of when you really love someone, you don't want to be just their friend (loose quote from Diary of a Mad Black Woman). Will it change over time? Alot of things do.
Would I personally respond to this e-mail? Probably not.