发誓绝对保密

swear absolute secrecy; be pledged to secrecy

发誓效忠

pledge allegiance (to)

发誓永不回去

swear never to return

发誓永远爱她

swear eternal love to her

手按《圣经》发誓

swear on the Bible; swear with one’s hand (resting) on the Bible

以名誉发誓

swear by/on one’s honour

法官提醒证人她已发过誓要讲真话。

The judge reminded the witness that she was under/on oath.

我不能告诉你她的名字，我向她发过誓。

I’ve given her my word, I can’t tell you her name.