kiratto
A brief, beautiful sparkle — a diamond catching the light, a star winking, or a glint of determination in someone's eye. Always a momentary, positive flash.
💡Noticing a ring on someone's finger — 'Her diamond ring flashed kiratto in the sunlight.'
彼女の瞳がきらっと光った。
Her eyes flashed kiratto.
The diamond on her ring caught the light and sparkled ___.
彼女の指輪のダイヤモンドが光を受けて○○光った。