"Fruit" here is a metaphor for "result" or "outcome." Alternate translation: "This gospel is having good results, more and more" or "This gospel is having increasing results" (See: [[rc://en/ta/man/translate/figs-metaphor]])
This is a generalization referring to the part of the world that they knew about. Alternate translation: "throughout the world" (See: [[rc://en/ta/man/translate/figs-hyperbole]])