ensure: implies a virtual guarantee: the government has ~d the safety of the foreign minister.   (guarantee保证保修a formal promise or assurance, especially that certain conditions will be fulfilled relating to a product, service, or transaction对产品服务交易的承诺，如we offer a 10-year guarantee against rusting我们保证十年不生锈，如the cooker is guaranteed for five years本炊具保修五年，如I guarantee you'll enjoy yourself我保证你会过得开心)   (（virtual.实际上的实质上implies a merely apparent difference between outward seeming and inner reality只是看起来有些不同，如the prime minister is the virtual ruler of his country首相是实际上的统治者，如本例virtual guarantee…实际上保证，可能没有明确保证，但无实质差别)


insure: sometimes stresses the taking of necessary measures beforehand to make a result certain or to provide for any probable contingency: careful planning should ~ the success of the party.    （contingency紧急迫切情况implies an emergency or exigency that is regarded as possible or even probable but uncertain of occurrence可能甚至很可能发生的紧急迫切情况，但不是必然发生，如contingency plans prepared by the Pentagon五角大楼准备的应急计划）     我们日常说的保险是这个词， 1、确保某一结果to make a result certain  2、预防紧急状况to provide for  contingency


assure: distinctively implies the removal of doubt, worry, or uncertainty from the mind: I ~ you that no one will be harmed.


secure: implies the taking of action to ensure safety, protection, or certainty against adverse contingencies:  ~ their cooperation by payment of a large fee.    （adverse不利的反对的逆风的，如such birds are experts of flight even when the wind is adverse即使是逆风，这种鸟也飞行自如）


ensure确保: 指实际上等同于保证 (garantee保证保修)，insure确保保险: 指提前采取措施，以确保某结果或预防紧急，assure确保使放心: 特指消除怀疑担心不确定，secure确保: 指面临不利紧急情况时，采取行动确保安全


记忆方法: 1）首字母AIES我和大海<==确保

         2）确保的意思是使确定mean to make a thing or person sure.