Befriend him. When I'm trying to get a villager out I write them two letters a day, with gifts, give them everything they ask for and talk to them as often as possible. But TTing will speed the process up considerably.
To decrease the chances of your other villagers pinging, start talking to them less. Stay on speaking terms so they WILL ping if they want to move, but don't do favours for them, write letters, etc. Concetrate on building a super strong friendship with the unwanted villager and they will be the most likely to leave.