You should be selecting the images in Lr and then doing a File > Export as Catalog, ticking the box to include Smart Previews. This produces a folder, which is what you should be sending her. It contains a Lr catalogue and folders for the Smart Previews, and she should be opening this catalogue. Now, it sounds like you are doing most of this.
Are you sending the whole folder, not just the Smart Previews? Is she opening that catalogue, or is she accessing the Smart Previews in some other way such as importing them into her own catalogue? If she is applying a Develop preset upon import, that might explain her seeing "a flash of what it should look like".
Another thing to look at is the default Develop settings. Maybe one of you has changed the default in some way? So in Develop, use Alt/Option and notice how the Reset button changes to Set Default. This would let you restore the default settings.
So we have narrowed down that it is the preset. When I send a catalogue of raw files, our screen shots match perfectly. BUT, when I have my preset applied, or she applies my preset, it looks different than it does on my computer (our screen shots don't match at all). So it is something I am doing wrong with the preset?