To be fair, that second attempt wasn't really an attempt on her life. Her father was just trying to put her in a dangerous enough situation that little Leslie felt threatened enough to use the powers he suspected her for having. The plot was partially foiled by Eli herself since she thought that it would lead to Leslie being the favored child and the two sisters switching places. The plan would have actually gone off without a hitch and Leslie would have been sent to the battlefield if the dumb Marquess had told his daughter the full plan rather than just that he was going to test Leslie's powers.
But anyways, that paragraph was just to say that the Sperado family has actually only made one attempt on Leslie's life.

ヾ(❀╹◡╹)ノ~When I first read the scene of the sister and the father planning against Leslie in the raw I was worried about wat would happen to Leslie. I thought they would come up with a complicated plan with the empress dowagers help to bring down the Salvatore or something. But when I heard the sister say that all they have to do is burn Leslie lmaooo I gave a big sigh of relief