lessen the intensity of something
assuage - ease
When you ‘assuage’ a feeling, you make it less painful or severe. For that reason, it is only used in relation to unpleasant feelings that are causing you distress, such as fears, anxieties, guilt, hunger, etc.
The CEO’s statement was designed to assuage fears that the company would be downsizing their operations.
Gary blamed himself for Sarah’s accident and nothing I said could assuage his guilt.
The assuagement of panic is a key component of the government’s strategy to deal with the crisis.