First - At beach your character have no idea she is a sharite ... so it makes no sense to attack her.
Whether your character or even you as the player know that is immaterial...you will be left no choice in the matter. Send her away enough times and she will return possessed by voices not of the tadpole or the absolute to either be accepted or to die by your hands. Refuse again and she will be driven to suicide by attacking your party. There is no other way...it will be something you will have to decide in the final game...either way that artifact goes with your party. And those "off topic" posts we were talking about earlier were rather relevant to what may be going on there with Shadowheart and why that artifact is forced to end up with you.
