kainrou

Bingham: Hiram Bingham, A Gilbertese-English Dictionary (1908, 1953). American Board of Commissioners for Foreign Missions.
Sabatier: Ernest Sabatier, M.S.C., Dictionnaire Gilbertin-Français (1954), translated by Sr. M. Oliva as Gilbertese-English Dictionary (1971). South Pacific Commission Publications Bureau.

Bingham

kaáinrou

n. an engagement of marriage.

vi. to be engaged.

kainrou

a. being engaged to marry from childhood, or simply being engaged.

vt. kainroua, kakainroua: to engage, to marry (formerly).