I won't make up stories, but I won't speak against myself.
"作り話はしないが自分の不利になる事は話さない"
- I won't make up stories, but I won't speak against myself.
- I'm not going to make anything up, but I'm not going to say anything that's going to go against me.
incriminateを使いたいです。
- I won't make anything up, but I'm not going to say anything that's going to incriminate me.
I don't make up stories, but I don't like to incriminate myself either.
この場合、次のような言い方ができます。
ーI don't make up stories, but I don't like to incriminate myself either.
「作り話はしないが、自分の不利になることも言いたくない」
to make up stories で「作り話をする・話をでっち上げる」
to incriminate oneself で「自分の不利になることを話す」
incriminate を使った別の例文：
ーThe lawyer told his client to be careful about what he said, so he wouldn't incriminate himself.
「その弁護士は依頼人が自分に不利になることを話さないよう、発言に気をつけるよう言った」
ご参考まで！
アメリカ合衆国 
カナダ 
