grin and bear it
grin and bear it {v. phr.}, {informal}
To be as cheerful as possible in pain or trouble; do something without complaining.
The doctor told Mrs. Howard that she had to stop eating sweets if she wanted to lose weight, and she tried to grin and bear it.
If you must have a tooth drilled, all you can do is grin and bear it.
Categories:
Source: A Dictionary of American Idioms