  We present a supervised secure entanglement sharing protocol via tripartite W
states for faithful quantum teleportation. By guaranteeing a secure
entanglement distribution in the charge of a third believed supervisor, quantum
information of an unknown state of a 2-level particle can be faithfully
teleported from the sender to the remote receiver via the Bell states distilled
from the tripartite W states. We emphasize that reliable teleportation after
our protocol between two communication parties depends on the agreement of the
supervisor to cooperate via taking the W states as both the quantum channel and
eavesdropping detector. The security against typical individual eavesdropping
attacks is proved and its experimental feasibility is briefly illustrated.
