[whistle] in the dark

to act as if one is not afraid or worried

The idiom "whistle in the dark" has its origin in the idea of using sound to dispel fear or create a sense of comfort in the darkness. The phrase metaphorically refers to an act of feigning bravery or confidence in a situation that is uncertain, dangerous, or unsettling. Just as someone might whistle to alleviate their fear when walking alone in the dark, "whistle in the dark" implies putting on a brave front or attempting to maintain optimism in the face of uncertainty or adversity.

Despite the challenging circumstances, the team leader decided to "whistle in the dark" and expressed unwavering confidence to motivate the team.
John tried to "whistle in the dark" by making light-hearted jokes to mask his anxiety during the nerve-wracking job interview.
The child, afraid of the thunderstorm, started to "whistle in the dark" by singing a cheerful song to distract themselves from the fear.
Susan, feeling uneasy in the unfamiliar neighborhood, tried to "whistle in the dark" and walked briskly while pretending to be self-assured.
The CEO, aware of the company's financial challenges, chose to "whistle in the dark" during the shareholders' meeting, emphasizing future growth prospects to instill confidence.