Most people that have Natto for the first time don't usually finish it because it has such a distinct flavour.
Natto doesn't agree with most people's taste buds. A lot of people who try it for the first time do not finish it.
ーAre you sure you would like to order this? Most people that have Natto for the first time don't usually finish it because it has such a distinct flavour.
「納豆を初めて食べるほとんどの方は、その独特の風味のため残されますが、本当に注文しますか？」
ここでの難しい味は、distinct flavour 「独特の味・風味」と言うと良いです。
ーNatto doesn't agree with most people's taste buds. A lot of people who try it for the first time do not finish it. Are you sure you want to order it?
「納豆はほとんどの人の味覚に合いません。初めて試される多くの人は残されますが、本当に注文されますか？」
ここでは難しい味を doesn't agree with most people's taste buds 「ほとんどの人の味覚に合わない」ということはほとんどの人が美味しいとは思わない、を使って表現してみました。
ご参考まで！
カナダ 
