如：I guarantee to pay off his debts. 我保證還清他的債務。
guarantee sb. sth =guarantee sth to sb. 向某人保證某事
如：The boss guaranteed his workers the full salary.老板向員工保證工資會全部發放。
guarantee sth.+adj. 保證某物如何
如：The art dealer guaranteed the picture genuine.那個畫商保證這幅畫是真的
guarantee that+句子
如：I guarantee that she will come 我保證她會來。