Ask specific questions and check if you receive answers on these questions In case you are using an Agency with email forwarding or other mail-services, and your correspondent is not responding on your specific personal questions, this could be a sign of being suspicious.
Another important thing is to confirm with her if your (original) letters indeed are reaching her.
Try to send copies of your original letters using postal mail or a fax machine at her office (if possible) and ask her if these letters are the same she received through the Dating Agency you are using.
I know examples that some Dating Agencies, with this kind of services, can create additional questions or add more text to your letters or even change your letters, just for the reason to keep you as long as possible as their customer.
These persons mostly don't answer your specific questions and don't give much personal information, but use general (predefined) text for their letters.
This is at least a sign that you have to be careful.
For example, some web sites have over 20.000 profiles, however this is not a reason to find any scam inside this Agency, it only gives you an impression how many profiles you can find on the 'entire' web.
So, the chance is present, but if you prepare yourself in a proper way, the risk of being scammed can be reduced to almost zero.
And you, blind of love, thinking about that beautiful young woman, are an easy potential victim for them.
But if this and all our other information is not enough for you to feel yourself 'well prepared' and certain then you always can decide to provide yourself with more information, tools or services.
It's you who has to make the choices, but making the wrong choice can cost you a lot of money.
Only use real, professional and verifiable agencies.
Check the agency If you visit the website of some Dating Agency, try to read all the information about this website before you start to browse through the ad's.