“Augustine defines this act of faith in his anti-Pelagian writings as thinking with assent, but the nature of such assent can be easily misconstrued if viewed through the lens of Cartesian or post-Kantian conceptions of volition. In contrast to these modern views, which for malign metaphysical reasons oppose free choice to all manner of determination, free assent for Augustine is in fact a species of desire. Significantly, Augustine uses assent interchangeably with consent, ‘(con-sentire, to “perceive with another”), an act that so to speak weaves together the work of two agents into one.’ And more significantly still, he makes this subtle shift in terminology in the context of explaining how faith is simultaneously the gift of God in us and in our power, indeed, in our power all the more that it is God’s gift in us. Assent, in other words, is inherently responsive, that is, simultaneously self-determined and determined by another without any inherent antagonism in that relationship. Indeed, it is precisely this co-action—my simultaneous determination to the good and by the good—that constitutes consent for Augustine.”
Michael Hanby, “These three abide: Augustine and the eschatological non-obsolescence of faith,” Pro ecclesia 14, no. 3 (Summer 2005): 352-353. The definition of consent comes from D. C. Schindler, "Freedom beyond our choosing: Augustine on the will and its objects," Communio: international Catholic review 29, no. 4 (Winter 2002): 637-638, another excellent article.