Message delivery approaches are disclosed through which senders can guarantee that their messages are desired by intended recipients. In one embodiment, a Sender agrees with a Service Operator to pay a fine for each message that is reported as an unwanted by its Recipient. For senders that agree in advance to pay such fines, Service Operators may provide preferential message routing around "spam" filters knowing that a guarantee is in place. If the Recipient reports that the message is unwanted, the Service Operator can penalize the Sender by a fine in the agreed amount, or by modifying a bond ratio value, rating, or other experience value associated with the Sender. Estimates of the complaints expected for a Sender may be used to determine the outcomes of the tests applied by the Receiver.