certainty: may stress the existence of objective proof: claims that cannot be confirmed with any scientific  ~.      objective客观mean to view things and events as apart from oneself是指"脱离自身的视角看问题"，反义词是subjective主观


certitude: may emphasize a faith strong enough to resist all attack: believed in his innocence with a fair degree of ~.    信念faith是指在没有证据的情况下的坚信     faith和certitude互释


assurance: implies confidence rather than certainty and implies reliance on one's own powers or methods, or trust in another: as much ~ as is ever possible where hurricanes are concerned.   如Masur led the orchestra with assurance马苏尔自信地指挥乐团


conviction: usually implies previous doubt or uncertainty and stresses a subjective, rational reaction to evidence: holds firm ~s about everything.   一般conviction仅表示坚定相信a strong opinion or belief，这条解释未采用      又如strong political/moral/religious convictions坚定的政治/道德/宗教信念，如'we shall, sir,' said Thorne, with conviction我们会的，先生，索恩坚定地说


certainty确信: 强调存在客观证据，certitude坚信: 强调信念足以抵御一切置疑，assurance自信: 表示自信(相信自身能力)而非对事物的确信，conviction坚信: 也表示坚信


记忆方法: 1）首字母CCAC纯纯此爱<==确信无疑            信是会意字，本意是"言语真实"，引申为"诚实可靠信用确实"，如信用表示"能履行承诺"。这个字在战国时使用频率很高，广泛用于人名和封号，还用于消息讯息，可能蕴含了对人言诚信的期望

         2）确信的意思是没有疑虑mean a state of being free from doubt.