solemn vow

a solemn oath/undertaking/vow, etc.

庄严的誓言、郑重的承诺、严肃的誓约等

I need a solemn vow you will never ambush a senior White House official again.

我需要你立一个不会再次伏击白宫高级官员的严肃誓言。

I've made a solemn vow not to over-indulge.

我发誓过不能放纵自己的。

Both sides were deeply in earnest, even passionate; an entirely sincere and cruel tyrant; a solemn vow.

双方都非常诚心，甚至是热情；一个真正的残酷的暴君；庄重的誓言。

On a more personal level, to learn English well is a solemn vow that we make to ourselves.

在一个较为个人的层面上，学好英语也是我们对自己作出的一份庄严承诺。

In the presence of God, our family and friends, I offer you my solemn vow to be your faithful partner in sickness and in health, in good times and in bad, and in joy as well as in sorrow.

在我主，众位亲友的面前，我献于你此庄重的誓言，无论染疾或是健康，无论顺利或是艰难，无论愉悦或是悲痛我都将忠诚与你相伴。

To give one's solemn oath. keep/ break a solemn vow

庄严地发誓给某人庄严的誓约履行[违反]庄严的誓约

Keep/ break a solemn vow

履行[违反]庄严的誓约

He made a solemn vow.

他庄严宣誓.

Last week I took a solemn vow that I would never say anything about a third party unless I was locked in a soundproof cell.

上周，我郑重发誓永远不会说出任何有关第三方的言论，除非我被锁在一个隔音的房间里。