Allay

[Little_Girl]

To make quiet or put at rest; to pacify or appease; to
quell; to calm; as, to allay popular excitement; to allay the tumult of
the passions.

[Dave Paprocki]

Diminish or put at rest (fear, suspicion, or worry)

[Marquetta]

To [quench], stop, [slake], [quell].