Which preposition to use with afeared

of Occurrences 9%

"Let's go," she whispered, "I'm afeared of the man.

on Occurrences 1%

"Dinnot be afeared on it Let's have a good un!" "Hurrah!" "Noo then," said John, "let's have yan more to end wi', and then coot off as quick as you loike.

Which preposition to use with  afeared