brave face, put on a

Also, put up a brave front.

1

Face adversity cheerfully. For example, Even though she had been passed over for promotion, she put on a brave face.

2

Try to appear brave even though very frightened. For example, Harry was terrified of animals, but his boss was a dog lover, so he put up a brave front. [Second half of 1800s]

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.