(1) 保证，担保 (make sure or certain of; guarantee) [T+n，T+that，T+n+ prep(of)]：～a good harvest/a favourable outcome to the negotiations/one's success 保证好收成/谈判获得有利的结果/某人获得成功; Come early to～ getting a good seat. 早点来以便确保找到好座位。 take measures to～good health and safety 采取措施以保证健康和安全; You must～that your television set is switched off at night/that you will arrive on time every day/that the work shall be done in the right way. 在夜里你一定要把电视机关上/每天都必须准时到/一定要把这项工作做好。～oneself of a good income 使自己获得高收入; 〖同〗 assure，guarantee，secure;

(2) 保证获得(有) (make sure of getting; secure) [T+n，D+n+n]： ～sb a good night's sleep/a good pass in the examination/an interview 保证晚上睡个好觉/考出好成绩/得到会见;He wrote one poem which～d his undying fame. 他写了一首诗，这使他得以获得不朽的声誉。These documents～to you the authority you need. 这些文件保证让你得到你所需要的权力。〖同〗 assure，secure;

(3) 保护，使安全，防止 (make safe; protect; guarantee against risk) [T+n+prep(against/from)]：～sb/oneself against (from) harm/danger 使某人/自己不受伤害/避开危险;～freedom against tyranny 确保自由不被暴君毁掉; Vaccination～s one against disease. 接种疫苗可以使人不得疾病。〖同〗 protect，guard，safeguard，secure;

→ en′surer n 保证人;

【注意】ensure和insure 都可以表示保证，如： ensure (or insure) victory (确保胜利)，但如果表示为生命或财产保险，则只能用 insure， 如：have one's house insured (为房子上保险);

【辨异】ensure与assure和insure的区别见ASSURE。