As a token of completeness, "十" is one of the numerals Chinese people like best. For example, the adverb "十足" (shí zú) means "utterly; completely".
1. 她魅力十足 (tā mèi lì shí zú) – she is really attractive!
2. 我对学习中文信心十足 (wǒ duì xué xí zhōnɡ wén xìn xīn shí zú) – I'm very confident in learning Chinese well).
Here, both "魅力" (mèi lì, charm, chrisma) and "信心" (xìn xīn, confidence) are abstract nouns, which have to be modified by such adverbs of degree as "十足", so the state of the abstract nouns can be described properly. When "魅力十足" and "信心十足" are used to describe something, they indicate the superlative degree.
魅力（mèi lì）、信心（xìn xīn）属于抽象名词。这类名词特别需要像"十足"这类程度副词的修饰。使用它们来做修辞，抽象名词的状态才能得到妥当的描述。因此，使用"魅力十足（mèi lì shí zú）"、"信心十足（xìn xīn shí zú）"这两个词组来描述事物的状况，程度相当于英语中形容词的最高级。
By contrast, the Chinese idiom "十全十美" (shí quán shí měi) is a superlative adjective. It means "perfect and flawless". Here, "全" and "美" refer to "good virtues and traits of a person".
与其相较，汉语常用成语"十全十美"（shí quán shí měi）也起到了高级别的修辞作用。它的意思是"十分美好的，毫无缺憾的。"成语中的"全"（quán）和"美"（měi）分别代表人美好的品质和特征。
"十全" means that one is perfect in will, wit, courage, temperament, morality, sensibility, manners, justice, virtue and emotion. Chinese people always sing high praise of somebody that is "智勇双全" (zhì yǒnɡ shuānɡ quán), or "both brave and resourceful" in English. However, according to the standard of "十全", even a perfect person is just qualified in these two aspects. So it can be concluded that Chinese people have been strict with one's quality since ancient times.
"十全"指的是人在志、智、勇、度、道、理、礼、义、贤、情这十个方面达到完美。中国人通常用"智勇双全"（zhì yǒnɡ shuānɡ quán）对人进行积极的评价。获此评价的人是才智和勇气兼备的人才。但按十全的标准来说，他或她也只达到了两层功力。可见，中国人对品德的追求自古就十分的苛刻。
"十美" means one is perfect in heart, spirit, soul, look, speech, thought, manners, behavior, appearance and morality, which comes down to "get refined both internally and externally".
It seems difficult to find one who meets all the requirements of "十全十美". We even cannot find its counterpart in English. It is more than being perfect or terrific. "You look terrific today!" We often hear in European or American films, where the heroine's delicate dress-up is complimented by the hero. However, if we translate "十全十美" into "terrific", it's something like wasting one's talent on a petty job. Here comes the question: under what circumstances should we use the idiom?
依据十全十美的极高要求，世间似乎难寻此真人。"十全十美"在英文中似乎也难已找到与之匹敌的形容词了。它的程度甚至超过了perfect或者terrific。我们常常在欧美影片中看到男主角用"You looks terrific today!"来评价女主角的精致。但，如果将此处的"十全十美"用"terrific"表示，就大词小用啦。那么，这个成语到底用在什么场合合适呢？
"十全十美" is usually used on occasions when people express their best wishes or compliments. For example, you can flatter somebody by saying, "你真是十全十美的人!" (nǐ zhēn shì shí quán shí měi de rén, you're gorgeous!), or you can send your best wishes to a newly-married couple, "祝你们十全十美！" (zhù nǐ men shí quán shí měi, wish you a happy life).
"十全十美"的汉语常用语境融合在表达美好祝愿、称赞（恭维）的场景中。比如，你可以恭维一个人说：你真是十全十美的人（nǐ zhēn shì shí quán shí měi de rén）！也可以对新婚夫妇说：祝你们十全十美（zhù nǐ men shí quán shí měi）！