1590s, "liable to make answer or defense, accountable," from Anglo-French amenable, from Old French amener "bring, take, conduct, lead" (to the law), from "to" (see ad-) + mener "to lead," from Latin minare "to drive (cattle) with shouts," variant of minari "to threaten," also "to jut, project" (from PIE root *men- (2) "to project"). The sense of "tractable" is from 1803, on the notion of "disposed to answer or submit to influence." Related: Amenably.
word-forming element denoting action, quality, or state, attached to an adjective or past participle to form an abstract noun, from Old English -nes(s), from Proto-Germanic *in-assu- (cognates: Old Saxon -nissi, Middle Dutch -nisse, Dutch -nis, Old High German -nissa, German -nis, Gothic -inassus), from *-in-, originally belonging to the noun stem, + *-assu-, abstract noun suffix, probably from the same root as Latin -tudo (see -tude).
<a href="https://www.etymonline.com/word/amenableness">Etymology of amenableness by etymonline</a>
Harper, D. (n.d.). Etymology of amenableness. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/amenableness