Accuracy of the translation of English manga? In general, what are the main problems that harm the accuracy of the english translation of a manga? After this process, considering that problems, "shades" and "feelings" in the dialogues, with respect to the same title in the original japanese language are preserved enough? 

Please, can you give me any example and why? many thanks. (:
Given a source material in language A, a translation to language B isn't going to be the same. For starters, the person translating is usually a different one, so they may not know the original intent the author had. Also, the language is different, so things may not carry over.

But this applies to translations of anything, not just manga.

Now, a decent translator should be able to minimize the loss. One could:


translate the text to something that results in an equivalent reaction to the reader (e.g. the original text had a pun, so translating it literally would make it so the reader won't laugh at it, so instead we make a different pun, and the reader still laughs) 
put in notes that explains why the source language text is written the way it is
rewrite the text a bit
...possibly other tricks
combination of above


Regarding the example of the first one: there's this text that I'm translating that relies on that "おっぱ" means both "breast milk" and "breasts". If I were to translate it literally, the pun would be lost. So instead I make the text vague with "they" about what a person is actually referring to, and not revealing it until the last moment. But this, again, loses something on what was in the source text. On the other hand, if I were to put in a translator note instead of that, that would have killed the pun (and therefore, the intended effect on the reader would be lost in translation), but would have preserved the meaning of the text.

Another example that often is problematic wrt translations to English is the matter of pronouns: there are different first person pronouns depending on the gender, or whether it's formal or informal situation. One could make it hard to translate without putting in a translator note if a character in the source material uses a different first person pronoun that the social protocol would expect, and other characters notice that.