grimly

This adverb conveys a heavy, somber tone, typically associated with hardship, severity, or a lack of optimism. It describes an internal state of resolve or a reaction to a bleak reality, often manifesting as a lack of smiling or a stern facial expression. While it can imply a frightening or forbidding quality, it frequently highlights a stoic endurance in the face of inevitable failure or pain.

In terms of register, it is common in narrative prose and formal descriptions of conflict or tragedy. It differs from "sternly" by adding a layer of hopelessness or grimness; where "sternly" suggests authority and discipline, "grimly" suggests a struggle against a dark or oppressive situation.