whistle past the graveyard

English

(idiomatic, US) To attempt to stay cheerful in a dire situation; to proceed with a task, ignoring an upcoming hazard, hoping for a good outcome.
(idiomatic, US) To enter a situation with little or no understanding of the possible consequences.

to try to be cheerful in the face of one's fears

Arabic: please add this translation if you can
Chinese:
Mandarin: 对着墓地吹口哨，指在害怕时故作轻松
Czech: please add this translation if you can
Dutch: please add this translation if you can
Finnish: pitää päänsä pystyssä
French: regarder ailleurs (fr)
German: (semantically close, but less idiomatic) der Angst ins Gesicht lachen (literally “to laugh into the face of fear”), die Angst weglachen (literally “to laugh away one’s fear”); (more idiomatic, but usually referring to emotions other than fear) zweckoptimistisch sein (literally “to be practically optimistic”), gute Mine zum bösen Spiel machen (literally “to keep a good face during the evil play”)
Hindi: please add this translation if you can
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Italian: please add this translation if you can
Japanese: please add this translation if you can
Korean: 두려우면서도 두렵지 않은것처럼 행동한다 (duryoumyeonseodo duryeopji anh-eun-geotcheoreom haengdonghanda)
Polish: robić dobrą minę do złej gry (pl) impf
Portuguese: manter as esperanças
Russian: мо́ре по коле́но (móre po koléno)
Spanish: poner buena cara
Vietnamese: please add this translation if you can

to ignore a bad situation