(mother gave it to her as they fled; father made it using a beam from their house before the Villain crushed it; she made it out of a stone given to her by her first and only friend before he was sucked into a vortex of evil; the stone reminds her to be brave, to love deeply and that kindness matter. Or you know…something equally sappy)
(Then it’ll turn out that the wood from which the house was made came from the World Tree, also knowns as the Magical Tree That Solves All Magical Problems By Unknown Ways. This, of course, will come in very handy when the unstoppable PLOT meets the unmovable PLOT HOLE).