他在法庭上发誓说实话。

tā zài fǎtíng shàng fāshì shuō shíhuà.

He swore to tell the truth in court.

她发誓要努力工作取得成功。

tā fāshì yào nǔlì gōngzuò qǔdé chénggōng.

She swore to work hard to achieve success.

孩子们发誓要互相帮助。

háizimen fāshì yào hùxiāng bāngzhù.

The children swore to help each other.