Preassurance

[Sommer]

The act of offering support or [reassurance] to someone before they have even expressed [concern] for the situation they are in. Sometimes a welcome gesture, but more often than not is not helpful to the situation and may worsten the concerns of the person or create concern where it previously did not exist.
Usually not a [malicious] gesture, sometimes just an act of ignorance.

[Renato]

An assurance given or received beforehand; a previous or prior guarantee.