Paraphrase:
In the first place, a contract to create a trust, ie wherein the founder undertakes to transfer the trust property to the trustees at some point in the future, will be governed by its own proper law which may not be the law which governs the trust itself. Likewise, a different law may govern the validity of a will from that which governs the trust thereby created. The ordinary rules governing choice of law in contract and the validity of wills will determine when this divergence takes place.