ensure、insure、assure、guarantee、pledge与promise这些动词都有“保证”之意。
ensure : 侧重使人相信某个行为或力量产生的结果。
- The airline is taking steps to ensure safety on its aircraft.
航空公司正在采取措施以确保其航班的飞行安全。 - The role of the police is to ensure (that) the law is obeyed.
警察的职责就是确保法律得到遵守。 - Their 2–0 victory today has ensured the Italian team a place in the Cup Final/ensured a place in the Cup Final for the Italian team.
今天意大利队2比0获胜，稳操胜券进入世界杯的决赛。
insure常与ensure换用，但前者多指经济方面的保证、保险。
- The house is insured for two million dollars.
该房子投保了200万英镑。 - All our household goods are insured against accidental damage.
我们家里所有的物品都保了意外损失险。 - I'm not insured to drive his car.
我没有相关的保险，不能开他的车。
assure : 侧重指消除某人思想上的怀疑或担心，从而有达到目的的保证感，但不如ensure普通。
- The unions assured the new owners of the workers' loyalty to the company.
工会向新企业主保证，工人们对公司是忠诚的。 - "Don't worry, your car will be ready tomorrow," the mechanic assured him.
“别担心，你的车明天就可以修好，”修理工向他保证。 - She assured him (that) the car would be ready the next day.
她向他保证说他的车第二天就能修好。 - The prime minister assured the electorate (that) taxes would not be increased after the election.
首相向选民保证选举后不会增税。 - You can rest assured (= feel confident) that I shall be there as promised.
你放心，我答应了就一定会到的。
guarantee : 指对事物的品质或人的行为及履行义务、义务等承担责任的保证。
- European Airlines guarantees its customers top-quality service.
欧洲航空公司保证为乘客提供最好的服务。 - The label on this bread says it is guaranteed free of/from preservatives (= it contains no preservatives).
这种面包的标签上写着保证不含防腐剂。
pledge : 正式用词，指通过郑重许诺、协议或立誓等保证承担某一义务或遵守某一原则。
- We are asking people to pledge their support for our campaign.
我们正请求人们承诺支持我们的运动。 - If you join the armed forces, you have to pledge allegiance to your country.
如果参军，你必须宣誓效忠你的祖国。 - So far, £50,000 has been pledged (= people have promised to pay this amount) in response to the appeal.
到目前为止，人们已承诺捐款5万英镑以响应这项呼吁。 - Both sides have pledged to end the fighting.
双方均已保证停战。 - I've been pledged to secrecy.
我已发誓保守秘密。
promise : 侧重表自己的主观意向，设法用语言使人感到稳当可靠。
- He promised faithfully to call me every week.
他信誓旦旦地保证每周都给我打电话。 - The government have promised that they'll reduce taxes.
政府已承诺要减税。 - Promise me (that) you won't tell him.
答应我你不会告诉他。 - I'll look for some while I'm at the shops but I'm not promising anything.
我逛街的时候找找，但不敢保证能买到。
