3 sentences

1. 我向你发誓，我绝不食言。

   wǒ xiàng nǐ fā shì, wǒ jué bù shí​yán.

   I swear to you that I will not go back on my word.

   Source: Dong Chinese Dictionary

2. 战士们誓要与敌人决战到底。

   zhàn​shì men shì yào yǔ dí​rén jué​zhàn dào​dǐ.

   The soldiers vowed to fight a decisive battle to the end.

   Source: Dong Chinese Dictionary

3. 他立下了庄严的誓言。

   tā lì​xià le zhuāng​yán de shì yán.

   He made a solemn vow.

   Source: Dong Chinese Dictionary