Definition
In almost every instance; nearly always.
十之八九
Nine times out of ten, he is late.
十之八九，他会迟到。
If you order the steak at that restaurant, nine times out of ten it'll be delicious.
如果你在那家餐厅点牛排，十之八九会很好吃。
Nine times out of ten, this method works.
十之八九，这个方法有效。