Especially this will be the case if the person of trust has used false promises to get information about the sexual relation from the child:
Often the person of trust tries to get information from the child hiding how this information will be used. The child assumes that the information will not be distributed or used against his will. Again, the result of the persecution process will be the loose of trust.
Even if the child by himself starts to talk about the sex to a person of trust, this usually will be based on such an assumption.
Thus, the only possibility to avoid this loose of trust is to observe the right of privacy of the child.