Translation:Enjoy your meal!
This is a very useful website for hearing pronunciation. https://forvo.com/languages/he/ You can copy from Duo and paste there, and it has pronunciation for many words and phrases. You can't slow it down, but you can play it over and over and listen hard for different parts of the word.
It's not great, some words the pronunciation is off even for English with native speakers (one even had four speakers that mispronounced the same word. Horrible.. Happened more than once. There's better choices, reverso app & website, http://www.reverso.com plus: https://www.pealim.com/ Http://www.morfix.co.il/en
Yet unlike Feliz Navidad, which, while acceptable in some English dialects, retains its Spanish characteristics because there is a way to express the same phrase in English, "bon appetit" does not retain its French context within English because it has been thoroughly integrated in the absence of a similar English phrase. A better analogue is with names of food dishes. For example, sushi is an English word even though its origin isn't English.
We might say "Enjoy your meal" or "Bon appetit." It's also okay to say just "Enjoy!" (But we can say "Enjoy!" with anything we give to another person to use; it is used for many things besides meals.) I've never heard "Hearty appetite" used alone, only in sentences such as "He has a hearty appetite" (which means "He eats a lot!"). See http://www.dictionary.com/browse/hearty for this usage--it's number 8.
The word טעם is used for taste in Hebrew. The root תאב, from which תיאבון and בתיאבון come, means desire, and is used for contexts which have to do with instinctive desires, such as hunger/appetite. The word תיאבון is ancient. It is highly likely that the phrase בתיאבון is similarly ancient.
While it is true that many of the influential figures in the development of modern Hebrew were Europeans who spoke or were well acquainted with French, one would expect the phrase to match meaning if borrowed. The mismatch, combined with the fact that "bon appetit" or its analogues were not used in Jewish dialects of European languages until very recently, suggest that בתיאבון is a longstanding traditional Hebrew phrase for the beginning of meal time, preserved in ritual context when that was the primary context for spoken Hebrew.
But I think it would be unusual for someone to tell you "good appetite" before you eat! I think it is much more common to say "bon appetit"! I see they are now accepting "enjoy your meal," which is what would likely be said if you aren't going to use the French phrase, though I think all the English-speaking world understands "bon appetit." I have never heard someone use "good appetite" in this way.
enjoy your meal is English no matter which country. Bon apetit is French even so it may be understood by some people in an English speaking country. Another example required? In Germany everybody understands and even native Germans use the word 'ciao'. Nevertheless is is still Italian. I would suggest to delete this French translation.