“保证的”用英语怎么说？

他对违反誓言和保证的行为给予严厉的惩罚.He imposed heavy penalties for breaches of oath or pledges.就算让我死去也不会有更可靠的保证的.If I were dead, that could not be surer than it is henceforth.她跟他一样,也怀疑这一保证的诚意.She doubted the sincerity of this assurance ...