The chubba mantest has never failed me.
It's simple really. Just imagine a female chuuba turned into a man. Will you still watch him? If yes, not a grifter; and if no, absolutely a talentless grifter

Korone, Maririn, Pekora, Gura, Ina for example all pass the test. They are funny and entertaining in their own right.

Can you take a guess who failed the test? Ahem Ahem.