Hi,
Which one(s) sound(s) o.k. to a native speaker?
(you can be called a knight because your valiant deeds speak volumes about your spirit)
1.1. You have proven to be worthy of a knight No.
If Tom is worthy of Mary, it means he deserves her, he meets her high standards.
1.2. You have proven to be worthy a knight (a tentative OK)
It needs to be You have proven to be a worthy knight .
(you can take on this job because you've just proven that you're fully qualified for it)
2.1. You have proven to be worthy of this job (a tentative OK) Yes. But it also suggests you deserve this job. There's a kind of moral or honorific sense attached to the word 'worthy'.
That's why a sentence like this would be rare in everyday business English.
2.2. You have proven to be worthy this job. No.
Clive