twinkle
Definitions
To shine with a gleam that changes from bright to faint.
A sparkle or gleam in the eyes, often indicating amusement or excitement.
A brief, flickering flash of light.
Examples
The stars began to twinkle in the clear night sky.
I saw a mischievous twinkle in her eyes when she told the joke.
The fairy lights on the tree started to twinkle as soon as I plugged them in.