noun, な adjective
This is not what you thought would happen during your deliberation. You thought it would be very normal. Instead, it's the opposite. It's full of wonder and mystery. It's marvelous
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
It's a mystery how time flies on your day off.
Marvelous things often happen when I am near Viet! The other day, for example, we were joining the end of a line but all of the people in front of us let us cut, one after the other.
We all depend on Koichi, but we also wonder why he seems so oddly cheerful all the time.