This prompt (in brackets) is taken from Complete the Story by Piccadilly Inc., which I got from the Scribbler box.

[She believed in me in a way no one else ever has and no one else ever will, and I betrayed her. The worst part is she doesn’t know. She still thinks] her first husband died of natural causes. She still thinks her second husband died at the hands of a robber. She doesn’t know her closest friend poisoned Gerald’s drink, and that the same close friend shot Robert through the heart with his own pistol, snatched from the mantel, the man too shocked to move or duck. She doesn’t know I relished her coming to me in her grief, clutching me, holding me, weeping into my shoulder. If only I could tell her why I did it: because I love her more than they could.

It’s okay. She’ll turn to me again once I’m done with Matthew.