英文里，如下得词都带有“保证”得意思：
Assuarance, commitment, guarantee, promise, and warranty
虽然如此，但内涵并不完全相同。
Assuarance 有“保证；保险得意思”，但这个“保证”并不具备法律效力，跟promise差不多，都是可能会违背得(Promises can be broken)，例如: I promise to visit you. I promise to pay you back. His assurance in his superiority did not make him popular.
相比之下，commitment就要郑重其事得多，（Commitment is suitable for those who want to make a declaration but with all the elements of dedication. A promise may or may not hold true in the future, but the commitments are more likely to be met.）也就是说，commitment需要有行动来支撑，例如：We made a commitment to keep working together.
guarantee 是一个法律用语，是一项非常正式得承诺(is to assure that something will get done right while promise is to commit to something or action) 例如：They are demanding certain gurantees before they sign the treaty.
而waranty 可以理解成“保修（期）”，这是一种gurantee，但是附带有条件，比如保修多久、哪些属于保修范围等等。
大家明白了么？
