I am looking for some advice about what I should do with regard to the girl I want to marry, but our relationship began through correspondence on the Internet?
We have to differentiate here between two important matters with regard to this issue. The ruling on this correspondence between men and women, and entering into relationships in which they get to know one another and talk to one another. This is something that is Haraam. It cannot be justified by saying that the intention of one or both parties is to look for a suitable partner to marry.
In the event that this has actually taken place where a person has started to get to know someone whether that was because he did not know that such relationships are Haraam. In general we do not advise these kinds of marriages, because the element of certainty with regard to the information acquired about the other party is not present; rather it is information that each party has given about himself or herself, which may lead to infatuation between the two parties before it has been established whether they are suitable for marriage or whether they have the qualities needed for a successful marriage. And Allah knows best