Grin and bear it
Definition 1 of 1
Pro Tip 1/3Suffer Silently
Used when you have to endure something tough but shouldn't complain openly. 
The training was brutal, but he grinned and bore it.
Pro Tip 2/3Remain Cheerful
Encourages keeping a positive attitude in a difficult situation. 
Though she lost the game, she just grinned and bore it.
Pro Tip 3/3Casual Context
Best used in informal conversations rather than formal or academic settings. 
In the middle of the crowded concert, we had to grin and bear it.