Significados de mirthful expression em inglês

I don't believe I can piece them together, with a bright, mirthful expression.

He had a good-humoured, jovial countenance, the mirthful expression of which even his sightless orbs could not destroy.

The colour rose, the form dilated, the lip quivered, the eye flashed light, and the mirthful expression heightened almost into the sublime.

She was a girl who was pleasant to look at when she laughed, for her features accommodated themselves so naturally to mirthful expression.

To my unutterable surprise I discovered a whimsical twinkling at the corners of his eyes and a mirthful expression of mischief in his countenance.