The translation of il est: The translation of il est:
Il est très simple in French uses the personal pronoun il. In this sentence, il refers to mon secret.
In Chinese, the normal way of saying 'It is very simple' is 很简单 hěn jiǎndān ('very simple'). There's no pronoun -- it's understood from the context that 'secret' is the subject -- and there's no verb 'to be' since Chinese doesn't need one with adjectives.
Translations omitting the pronoun
Of the 30 translations using the 很简单 hěn jiǎndān ('(is) very simple') pattern, fifteen use no pronoun. That amounts to only half of the translations using this pattern.
Translation as 它 tā
Almost as many translators choose to literally translate the pronoun.
For a third-person pronoun, Modern Chinese originally had the word 他 tā, which could be equally used for 'he', 'she', or 'it'. But in the 20th century, the Chinese decided that the written form of this pronoun needed to be distinguished for gender, just like the Western languages. Thus were born three separate characters to write the same word:
他 tā 'he' or 'it' (living things, usually human, mostly male)
她 tā 'she' (female living things, usually human)
它 tā 'it' (animals of either gender, non-living things)There's a fourth character, still used on Taiwan: 牠 tā 'it' (used for animals, whether male or female). A fifth, rather rare, character is 祂 tā 'He', used for God.
Since the standard equivalent for 'it' is 它 tā, it's perhaps natural that some translators are tempted into using 它 tā for il in this sentence. And indeed, altogether fifteen of the 30 translators who use this pattern use 它 tā. This results in translations like 它很简单 tā hěn jiǎndān ('it is very simple').
Since the French uses il, it's not surprising that twelve of these fifteen translators are translating from the French. But curiously enough, there are there are also 11 translators working from Katherine Woods' English who use the 很简单 hěn jiǎndān sentence pattern -- three of whom use 它 tā. Since Woods' version doesn't use the 'it is very simple' structure at all, let alone a pronoun for 'it', we can only surmise that these translators have supplied a pronoun themselves, have been peeking at the original French, or have copied other translations.
There is a problem with using 它 tā, and that is that it makes for rather stilted prose. It was only around 1918 that Chinese began to use 它 tā to refer to abstract concepts (as opposed to concrete 'things'). Previously it simply wasn't a part of proper Chinese prose. It's now established in the written language but is still not so common in speech. The use of 它 tā here verges on translationese, a kind of language perpetrated by students who have got used to using literal translation as a crutch and can't shake the habit, and poor translators who have lost their sensitivity to their own language.
Translation using 'this' 这 zhè
One translator uses the expression 这也很简单 zhè yě hěn jiǎndān 'This is also very simple'. This looks like a translation of il, but in fact probably isn't.
这也 zhè yě is a common enough collocation in Chinese. 这 zhè refers to a phenomenon or situation in general. 也 yě normally means 'also', but here it doesn't actually mean 'also' at all. It's a very natural way in spoken Chinese of softening what is being said. By saying 这也很简单 zhè yě hěn jiǎndān, the fox is playing down the difficulty of the secret, taking an attitude of gentle explanation. 这个很简单 zhè-ge hěn jiǎndān 'this is very simple' would sound mildly boasting, arrogant, or assertive.
Très
Très ('very' in English) is meant to emphasise how simple the secret is. When you consider it, très is a pretty simple, everyday word. So is 'very'. So you'd think that translators would translate it with a very simple, everyday word.
Mostly you'd be right. For instance, all but one of 24 translators working directly from the French use the very ordinary, straightforward word 很 hěn ('very'), as do thirteen translators working from the English of Katherine Woods. But 很 hěn has become rather weak in modern Chinese, so a few translators, mainly from the English, decide to beef it up a bit:
Six translators use 非常 fēicháng 'very, extremely', which makes the secret just that much more emphatically simpler.
Two translators use 十分 shífēn 'quite', which is also more emphatic.
The real blockbuster is the translator who decides to go the whole hog with 再简单不过的 zài jiǎndān búguò de 'exceedingly simple, couldn't be simpler'!
On the other hand, two translators leave out 'very'. Both translators use the noun in apposition construction, 一个简单的秘密 yīge jiǎndān de mìmì 'a simple secret', again translating from Katherine Woods' English.
So the translations run the gamut from 'exceedingly, could not be more', to leaving 'very' out altogether!