guarantee

Compared meaning: promise or make sure something is true (verb).

比较义项：保证、确保、担保（动词）。

• assure

  Assure means to tell a person something to remove their doubt or worry; it takes a person as its object, unlike ensure and guarantee.

  assure 意为告诉某人某事以消除其疑虑或担忧，宾语通常是人，这一点与 ensure 和 guarantee 不同。

  The pilot assured the nervous passengers that the turbulence was normal.

  飞行员向紧张的乘客保证，这次颠簸是正常现象。

• ensure

  Ensure means to make certain that something happens or is true, focusing on actions or conditions rather than reassuring a person directly.

  ensure 意为确保某事发生或属实，侧重于行动或条件，而不像 assure 那样直接安抚某人。

  The manager ensured that every fire exit remained unlocked during the event.

  经理确保活动期间每个安全出口都保持畅通未上锁。

• guarantee 本词

  Guarantee expresses a strong, often formal promise that something will definitely happen or be true, implying responsibility or consequences if it fails.

  guarantee 表示强烈、通常正式的承诺，保证某事必定发生或属实，往往意味着若未兑现需承担责任或后果。

  The manufacturer guarantees the laptop for two years against any defects.

  制造商为这台笔记本电脑的质量缺陷提供两年保证。

Assure, ensure, and guarantee all mean making something certain or believed, but in different ways. Assure means calming a person's doubts. Ensure means acting to make sure something really happens. Guarantee is a strong, formal promise, often with responsibility if it fails.

这三个词都表示让人相信某事为真或会发生，但方式不同：assure 重在对人消除疑虑，ensure 重在通过行动使某事确实发生，guarantee 则是正式而有力的承诺，常隐含责任或后果。

Compared meaning: a written promise to repair or replace a product (noun).

比较义项：（商家或厂商就产品维修或更换所作的）书面保证（名词）。

• guarantee 本词

  More general and informal; often implies a simple promise of quality or satisfaction, without specifying a fixed time period or legal terms.

  更笼统、更口语化；通常只是对产品质量或满意度的简单承诺，不一定说明具体期限或法律条款。

  The store offers a guarantee on all new products, but doesn't say for how long.

  这家商店对所有新产品提供保证，但没有说明期限多长。

• warranty

  More formal and specific; usually a written document stating an exact time period and the conditions under which repair or replacement is covered.

  更正式、更具体；通常是一份书面文件，注明确切的期限以及维修或更换所适用的条件。

  The new washing machine comes with a two-year warranty covering parts and labor.

  这台新洗衣机附带两年保修，涵盖零件和人工费用。

Guarantee and warranty both mean a written promise to repair or replace a product. Guarantee is general and informal, a promise of quality with no fixed time period. Warranty is more formal, usually stating an exact time period. Not covered: guarantee meaning to promise something.

两个词都指产品出问题时可获维修或更换的书面承诺，但 warranty 更正式、常带明确期限，是零售和法律语境下的标准说法；guarantee 更通俗、笼统，也更常用于日常口语中表达对质量的一般承诺。这里不比较 guarantee 作“保证，担保（某事会发生）”的更宽泛义项。