The fact that you are Italian isn't a problem. You can clearly speak two languages so you are intelligent. You just need to be more careful and get to know what to look out for in these mails.
We are always here if you are in any doubt. The best thing to do is to find another Italian who has worked in the UK and find out how she got the job.
Another idea
http://www.bapaa.org.uk/displaypage.asp?page=5The British Au Pair Agencies Association (BAPAA) is the only recognised Trade Association for the au pair industry in Britain. This organisation was formed in 2003, on a non-commercial basis, with the purpose of setting standards for the au pair industry and protecting the au pair experience as a rewarding cultural exchange programme.
Members must meet firm business and ethical standards and, in turn, agree to abide by BAPAA's Code of Conduct, which signifies competence, fair dealing and high integrity.
This appears to be a much safer and better way to find an au pair job.
Q Why do I have to use an agency? Can I not just pick a family from an internet site?
A You should never look for, or accept a family, that you have found on the internet. It’s not a safe way to travel and work as an au pair. Always use a reputable BAPAA agency (see list of BAPAA member agencies in the Directory). A BAPAA agency assists with the careful matching of an au pair to vetted families in Britain. Many agencies look after the same host families year after year; they know the families well and this ensures successful and safe placements. Once in the UK, you will be well looked after by the BAPAA agency you choose to use.
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Q There are no au pair agencies in the country where I live. What should I do?
A Contact one of the BAPAA agencies on this site and they will advise you who to contact and what the next step is.
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Q Do I need to provide the agency with a medical report and police check?
A A Medical report is essential and so is a police check. It’s very important that the BAPAA agency ensures that you are physically and mentally fit to work as an au pair and also that you have no criminal background.
Also see this page
http://www.bapaa.org.uk/displaypage.asp?page=41It will be more difficult to find a job, but the risks of having your money stolen or getting into trouble are too great to take a risk.
I cannot give my personal recommendation to these people as I have no experience in this area, but it appears to represent the proper way to find an au pair job to me.
I hope this is of some help.