Treówsian
Bosworth & Toller Anglo-Saxon Old English Dictionary - treówsian
According to the Old English Dictionary:
trýwsian;
- treówsian
- p. ode. I. to engage, pledge one's self :-- Him cómon ongeán . vi. cyningas and ealle wið trýwsodon (wið hine getreówsodon, col. 1), ðæt hí woldon efenwy[r]hton beón on sǽ and on lande six kings came to meet him, and all solemnly engaged to co-operate on sea and on land, Chr. 972; Th. i. 225, col. 2. Se munuc ðe mynster næbbe cume tó scíre biscope and trýwsie (-ige) hine sylfne wið God and wið men ðæt hé þreó þing healdan wille, L. Eth. II. to prove one's self to be true, to clear one's self from a charge of untrue conduct :-- Gif hé hine trýwsian wylle, ðaet hé tó ðære lǽne fácn ne wiste, ðæt hé mót, L. Alf. pol. 19; Th. i. 74, 7 note, [pas weord ich wulle þe treosien þurh mine god I will prove to thee the good faith of these words by an oath, Laym. 8489. Trousien, 8315, The word also means to trust :-- þe king him treousede on, 9308.] v. ge-treówsian; treówan. treowsian