You should try to explain in English to your best ability, even if you disagree with the answer.
You should try to answer in English to your best ability, even if it is not your honest opinion.
"本当の意見と違っても英語で説明できる立場を取るべきだ" は以下の回答のように言えます。
「You should try to explain in English to your best ability, even if you disagree with the answer.」
「You should try to answer in English to your best ability, even if it is not your honest opinion.」
「to your best ability」は「最大限に」「出来る限り」という意味です。
「even if it is not your honest opinion」は「たとえそれが自分の本当の意見でなかったとしても」
文章構成は出来る限りナチュラルな表現になるように変えています。
I hope this will help you.
お役に立てば嬉しいです