The scene I wanna try is that moment I mentioned in my guy's sheet. In his moment of sympathy before each kill, he gives the target a chance to say their final words. So in this case, my guy would have the blade in such a way that your guy couldn't move before waking him to take his dying words. It would be then that your guy does his magic in keeping his heart beating :P

As for something better? I've always though a consistent job would be great incentive. Like the prince could hire him as a secret bodyguard and/or information gatherer. This would have the assassin reporting to him every few nights and/or basically stalking his every move. This would work also to get a better feel of the politics of the land, and perhaps get the young man on the throne safely :P

Or, alternatively, he could ask for the assassin's help in escaping all the crazy politics and collect a king's ransom from, well, the king :P Not knowing where else to go, the prince could follow the assassin back to his home after they collect the ransom. In that option, we'd be exploring the Fae side of things more, but I see eventually going back to the kingdom after say, word of his sister's death? He would go back to find out what happened, and at this point the two of them would be close and the assassin would go with him because he felt like it.

Those are just my ideas. . . . . .