Reference for Kiddushin 20:14
והכי שלח ליה שמעתי עליך שאתה אומר ארוסה בת ישראל אוכלת בתרומה ולא חיישת לסימפון שלח ליה ואתה אי אתה אומר כן מוחזקני בך שאתה בקי בחדרי תורה לדרוש בקל וחומר אי אתה יודע
But if you say that it effects onl kiddushin [i.e., erusin], why is he certain in the one case and doubtful in the other? - Said R'Nahman B'Isaac: After all, I can tell you that [the reference is to] intercourse with huppah and money without huppah. And as to your objection, here there are two, while there is only one: nevertheless the a minori proposition holds good, and it was thus he sent word to him: If a Gentile bondmaid, whose intercourse does not permit her to eat of terumah even after huppah, yet her money even without huppah authorizes her to eat terumah,' then this one, whose intercourse when accompanied by huppah permits her to eat terumah, Surely her money even without intercourse permits her to eat terumah.