assure sb that + clause
that从句表达保证的具体内容。
He assured me that the package would arrive on time.
他向我保证包裹会按时到达。
使确信；向……保证
assured — past of assure
确保和保障；保证；使(某人)对(某事)有信心；使安心；保证
to tell someone firmly and confidently that something is true, especially to stop them worrying
确保和保障；保证
To make sure and secure; ensure.
使(某人)对(某事)有信心
To give (someone) confidence in the trustworthiness of (something).
使安心
To reassure.
一般现在时
I assure you that everything is fine.
我向你保证一切都没问题。
一般过去时
He assured me of his support.
他向我保证了他的支持。
现在完成时
They have assured the safety of the product.
他们已经确保了产品的安全性。
注意：assure 后接人时常用结构 assure sb of sth 或 assure sb that...
She assured me that the train would leave on time.
她向我保证火车会准时出发。
用法提示：assure 作及物动词，表示“向某人保证”，后接 that 从句。
The guide assured the tourists of a beautiful view from the top of the mountain.
导游向游客保证，从山顶能看到美丽的景色。
用法提示：assure 与 of 连用，表示“使确信”，后接所保证的事物。
Please assure yourself that the door is locked before you leave.
离开前请确认门已经锁好。
用法提示：assure oneself 表示“弄清楚、使确信”，后接 that 从句，动词原形用于祈使句。
that从句表达保证的具体内容。
He assured me that the package would arrive on time.
他向我保证包裹会按时到达。
of后接名词或动名词，表示保证的事物。
The manager assured us of her support.
经理向我们保证她的支持。
直接接宾语，表示确保某事物。
The new contract assures job security for employees.
新合同保证了员工的工作安全。
assure常用于向人保证，ensure则侧重确保事情发生，不直接作用于人
guarantee语气更强，常涉及法律或正式承诺；assure更强调消除疑虑
convince强调通过证据或理由使人信服，而assure侧重于口头保证和安抚
reassure特指消除已有的忧虑或不安，assure则更广泛地用于一般保证
grammar · medium
易错句子I assure to finish the report on time.
正确表达I assure you that I will finish the report on time.
assure后不能直接跟不定式，需接sb. + that从句或sb. of sth.结构。
grammar · medium
易错句子Please assure the door is locked before leaving.
正确表达Please ensure the door is locked before leaving.
assure用于使人确信，ensure用于确保某事发生；此处应用ensure。
grammar · medium
易错句子She assured that everything was fine.
正确表达She assured me that everything was fine.
assure是及物动词，必须接宾语（被保证的人），不能直接接从句。
assure 强调向人保证以消除疑虑，而 ensure 强调确保某事必然发生。
assure 通常用于消除人的疑虑，而 insure 主要指为可能发生的损失购买保险，美式英语中也可表示确保（同 ensure）。
向某人保证某事
The manager assured us of the product's safety.
经理向我们保证了产品的安全性。
确保……
Please assure that all doors are locked before leaving.
请确保离开前所有门都锁好了。
放心；确信
You can rest assured that your information is confidential.
你可以放心，你的信息是保密的。
保证质量
Our company constantly strives to assure quality in every product.
我们公司不断努力确保每一件产品的质量。
保证安全
The new regulations are designed to assure safety at work.
新规定旨在保证工作安全。
确保成功
Hard work alone cannot assure success; you also need strategy.
仅靠努力不能确保成功，还需要策略。
as- (to) + sure (certain)
en- (cause to be) + sure (certain)
in- (into) + sure (certain)
Assure 旨在建立或增强信心。
Assure 强调消除疑虑，确保确定。
Assure 有助于建立或维护信任关系。
Assure 提供一种安全感和保障。
Assure 常涉及对事实或承诺的验证。
放心
Rest assured, the matter is being handled.
请放心，这件事正在处理中。
向某人保证某事
I can assure you of our full cooperation.
我可以向你保证我们会全力合作。
我向你保证，我们不是。
In The Princess Bride, Vizzini assures the Man in Black that they are not the Dread Pirate Roberts.
在电影《公主新娘》中，维齐尼向黑衣人保证他们不是恐怖海盗罗伯茨。
我向你保证，我不是女巫。
The woman assures the court that she is not a witch.
这个女人向法庭保证她不是女巫。
Dictionary facts from ECDICT, WIKTIONARY.