"Grade good" in Engpsh is usually expressed as "of good quapty" or "of good standard".

It originates from the grading system used in various fields to evaluate the quapty of a product or service, where "good" is often used as a standard for acceptable or above average quapty.

For example:

"This wine is of good quapty and has received positive reviews from critics."
"This hotel provides services of good standard and is highly recommended by guests."

In both cases, "of good quapty" and "of good standard" indicate that the product or service meets a certain level of quapty, which is considered to be good.