You could say おいしいですわ、日本人ですわ、行きますわ or おいしいわ、日本人だわ、行くわ. The difference is politeness. The first ones are polite, and the latter ones are casual. As other respondents answered, わ is female language in Tokyo dialect(therefore you often hear it in dramas and movies), but not in other areas.

わ is simply more emotive. In 標準語 (standard Japanese) it is feminine but in other dialects it is also common for men

same meaning,but "わ"commonly be used by woman.

わ　is women's word. です　is more polite so おいしいですわ。　

im still learning japanese but, i think the diference is おいしいです is more correct than the other, it still the same but the first one is more afirmative, like "it's delicious" and the second one is more like "delicious". that hapens too with 日本人です and 日本人だわ.like in "doudatta, hajimete no tokyo wa" its a non correct way to say id but is very common.hope this can help you Ps:sorry i didnt write on kanji and hiragana, this keyboard doesnt allow me to do it.and...im still learning english so please forgive my gramatical mistakes.