I agree with Nelle's post. I think it's an opportunity to gently teach her that not everything turns out ok. I think we underestimate 3 year olds sometimes!

I personally wouldn't lie about it. Just like I wouldn't try and replace a pet goldfish that had died without them knowing.

And part of her simply accepts it because I am her mother, and she knows I tell her the truth, and she believes what I say.
I think that's the most important thing. I wouldn't risk losing that.