First off, kudos for having the courage to take on such a challenging proposition.

Second, and here’s that pesky “but”…

Not being a native speaker is a real handicap when writing in a second (or third, or fourth…) language.

Here’s a non-exhaustive list of giveaways in the above story that make it look like you’re not a native speaker (ignoring the fact that you’ve already stated as much :)).

Please note that this is not about being a grammar nazi (which is an expression I don’t much care for). It’s intended to point out that there is good reason why being a native speaker is (usually) a critical, though insufficient, requirement for being an effective copywriter.

• “The answer is positive and I’ll explain you why” — should have been “The answer is ‘yes,’ as I explain below”
• “I found myself wondering if one day I could have been good at working as a copywriter using a language that was not my own.” — should have been “I found myself wondering if one day I could become a good copywriter in a foreign language.” (or “in a second language.”)
• “language lover” — should have been “lover of languages”
• “enter the mechanisms of a foreign language… without possibly creating unpleasant misunderstandings” should have been “become fully aware of the intricacies of a foreign language… without unfortunate errors”
• “Nonetheless, I was sure that entering the world of copywriting without even try to use English as my first option (I am Italian and you hopefully didn’t notice) would have mean to lose countless opportunities.” -> “Nonetheless, I was sure that breaking into copywriting while avoiding English (I am Italian, which I’m hoping you didn’t notice) would have meant losing countless opportunities.”
• “That was the time I made the terrible choice to ask a bunch of colleagues on LinkedIn to solve my painful dilemma.” -> “That’s when I made the big mistake of asking some colleagues on LinkedIn for advice with this dilemma.”
• “Needless to say, as soon as I published my question that sounded like a “Should I try or should I forget this option?”, I was immediately attacked by several English native speakers who listed many reasons why they thought it was impossible for me to even think of reaching such an understanding of their language to cope with the writing skills that being a copywriter requires.” -> “Needless to say, the responses to my “Should I try or should I forget it?” question were quick and painful. I was attacked by several native English speakers who listed many reasons why they thought it was impossible to acquire the language skills needed for copywriting in what was for me a foreign language”
• “The average of the answers where mainly oriented towards what some could define a ‘grammar-nazi approach’:” -> The typical answer was what many would call the ‘grammar-nazi approach:’”
• “Considering that I was and still am a professional who always want to do her job at her best, the only result I got by this shy try to convince myself I had an opportunity to be a good non-native speaker copywriter was a terrible sense of inadequacy.” -> “Considering that I was, and still am, a professional who always wants to do a great job, the only thing I got out of posting that question was a terrible sense of inadequacy.”
• “At the beginning” -> “At first”
• “Everything went the way I hoped for” -> “Everything went the way I had hoped”
• “One day, though, I was offered a job in an international company that run several businesses oversea and I was asked to create content for social networks and ads that had to be addressed to the American public.” -> “One day, though, I was offered a job at an international company that runs several businesses overseas, and was asked to create content for social networks and ads targeting the American public.”
• “my first works” -> “my first attempts”
• “I was beginning to feel I didn’t have any chances to succeed, until something beautiful happened: I was commissioned to create a copy for a video that celebrated” -> “I was beginning to feel like I didn’t have a chance of succeeding. Then, something beautiful happened. I was commissioned to create copy for a video celebrating”
• “As an Italian, I knew I didn’t know enough about the values, the feelings, the language that was linked to that particular semantic field for Americans and I was scared I could offend someone with a not appropriate use of terminology or imaginary I was going to use for my copy.” -> “As an Italian, I knew that I didn’t know enough about the values, feelings, and language linked for Americans to that particular semantic field, and I was afraid that I’d offend someone with potentially inappropriate wording in my copy.”
• “This awareness brought me to watch every video, to listen to every speech, to read every line dedicated to that particular theme by US Presidents, Veterans and common people, and which I could find surfing on the internet.” -> “This concern led me to watch every video, listen to every speech, and read each line that I could find on the Internet, that addressed that particular theme, whether by US Presidents, veterans, or by everyday people.”
• “After a few days,” -> “A few days later,”
• “made an entire congress of Veterans urging for that work to be copyrighted” -> “had an entire congress of veterans urging that this work should be copyrighted”
• “before I can write texts which don’t need supervision and that are grammatically perfect” -> “before I can write text that doesn’t need to be edited, and that’s grammatically perfect”
• “languages have their rules and they must be respected” -> “languages have rules that have to be followed”
• “advices” -> “advice”
• “understanding of values of cultural groups” -> “understanding the values of cultural groups”
• “And, above all, with being a good communicator.” -> “Above all, being a good copywriter means you have to be an effective communicator.”

Does all this mean that you can’t work as a copywriter in English? No. However, it does mean that you should seriously consider whether or not to publish in English without a native speaker editing your writing before publication, especially when trying to make the case that you can write effectively in a foreign language.

My personal bottom line is that you write very well in English for a non-native speaker. None of the above errors make it impossible to understand your meaning. However, in my opinion, that’s not a high enough bar for professional writing in English. To do that, again, in my opinion, requires the sort of learning that happens only when you immerse yourself in that foreign language and the idioms of your target audience for years.

I should know. I’m not originally from an English-speaking country, but I spent three years in the US from age 10 to age 13, attending public schools, which allowed me to learn idiomatic English. I’ve also (intentionally) read almost exclusively in English since then. Finally, I’ve been living in the US for the past 26+ years, working in very communication-intensive fields.