In preparation for your coming, I used my sight to look over the world and through the mists of time. I have found what it is you seek.
In the War of the Ancients, two lovers fell together in battle. Where they took their last breaths, a tree known as the heartswood grew, a symbol of their undying love.
That should be enough to tempt a succubus. You will find it in the ruins of Ordil'Aran in the northwestern part of the forest of Ashenvale.
Rewards
No item rewards listed. Current Forever XP and money rewards are unknown.