German term (edited): dinglich wirkende Übertragung

Depending on your target audience, the translation of this term may need to be accompanied by an explanation.

This expression relates to a distinctly German legal concept which does not exist in common law (Anglo-American) legal systems. Under German law, the transfer of ownership (Übereignung) of property is subject to the so-called principle of distinction (Trennungsprinzip). For ownership of something to be transferred, there must be both a "real agreement" (dinglicher Vertrag) and a transfer of possession (Übergabe).

In very broad terms, the real agreement is the legal transaction which underlies the transfer (a sale, a gift, a barter, etc.). The transfer of possession is what completes the transaction and makes ownership pass between the transferor and the transferee.

This has nothing to do with rights in rem or in personam. A right in rem is essentially a right relating to a thing (a right to possession of a car). A right in personam is a right against a person (a right to payment of money from John). The distinction between these two concepts has nothing to do with the distinction between real agreements and transfers of possession (which I suspect the rest of your sentence which was cut off relates to).

As mentioned above, this translation might need to be accompanied by an explanation of some kind. When I encounter this kind of term, I typically add a footnote making the reader aware that X is a translation of the German legal Y. The reason for this is that the average English-speaking lawyer will have no idea what a "real agreement" is, as this is something that does not exist in Anglo-American law.