國際私法選法理論歷經20世紀後半葉的革命性演進，涉外事件實體正義的重視似為一項重要趨勢，本文首以若干身分法律關係為例，說明實體法律核心價值與選法理論之牽連與交錯，藉以指出選法過程中實體考量之重要性與必要性；其次，本文即廣泛自學術論述、司法案例及國際公約等面向，歸納跨國信託法律關係之實體法律核心價值，藉由綜合觀察權威著作的論述內容，並擷取、頗析若干歐、美、澳等不同地點、在不同時期的司法案例，可知委託人創設信託關係之正當合法意願與期待應受尊重與落實，乃（意定）信託關係的共同核心價值；而此一核心價值，與海牙信託公約所隱含之精神亦正相符合。職是，本文即以觀察所得的信託法核心價值為基石，嘗試提出以實體法律核心價值為核心之國際私法選法理論，由實體價值理論內容的建構、實體價值理論的適用模式、以及實體價值理論與傳統及其他現代選法理論之比較等觀點，闡釋實體價值理論的可行性。本文亦主張在選法過程中，無論採行方法論模式或選法規則模式，均應以系爭事件實體核心價值做為選法之最高指導原則，若就跨國信託法領域而言，即為委託人創設信託之合法意願。

In the light of the criticisms of Cook, Lorenzen, Yntema, Cavers, and many others, the classical vested rights approach that Joseph Beale advocated and promulgated in the First Restatement is largely considered passé, mainly because its hard-and-fast conflicts rules constructed by predetermined connecting factors failed to take into account the substantial tenor of each law pattern during the choice-of-law process, thus produced unjust result inevitably. To pursue for justice with flexible functional alternatives, countless law periodicals that proposed new methodologies, such as Governmental Interests Analysis by Currie, Better Law Theory by Leflar, The Most Significant Relationship Test laid down in the Second Restatement by Reese, and Comparative Impairment Approach by Boxter, just to name a few, led to the modification of judicial precedent finally gave rise to the Conflicts Revolution.Winning the war with their flexible functional analyses, however, the modern theories create new battle, making the conflicts world much more chaotic than ever. Namely, modern approaches solved the unjust result said to be produced by the traditional rigid rules on the one hand, they sacrificed the certainty and predictability of legal system on the other. This article, therefore, attempts to promote a new thinking of choice-of-law methodology based on substantive values. For the sake of theoretical structuring, specific attention will be paid to the substantive core value of transnational trusts.Following a brief introduction of this article in Part I, Part II is a discussion of the inter-relationship between substantive value and choice-of-law theory. In Part III, the author induces the substantive value in transnational trusts as ”the fulfillment of the justified intention of the settler” by introducing opinions by several prestigious commentators from different countries, cornerstone cases by different tribunals, and the regulations in The Hague Trusts Convention. Based on the substantive core value in transnational trust, Part IV examines the methodology this author tries to advocate by means of explaining its application and comparing with both traditional and modern theories. And Part V is the conclusion of this article.