How we cite our quotes: (Line) The only manuscript in which the poem is found has been damaged by fire, so that parts of it are indecipherable. (Crazy, right?) These sections are indicated by ellipses in the text.
Quote #1
I have now come here
on the deck of a ship, and now you shall know
how you might think in your heart about
the heartfelt love of my lord. (8b-11a)
The messenger has come to the lady hoping to effect a change in her state of mind. He wants her to feel sure of her lord's love. Here he promises that the lady will feel that way. He's very sure of himself, this guy (or piece of wood).
Quote #2
I dare promise
that you will find there a gloriously assured commitment. (11b-12)
Saying that he "dare" promise the lady's going to find a commitment in her and her lord's heart acknowledges that the outcome of his message is far from certain, despite the confidence of the previous lines.
Quote #3
Begin to seek the ocean, the native land of seagulls,
board a seaworthy ship so that south from here
you may find the man beyond the ocean-path,
where your lord is in expectation of you. (26-29)
Saying that her lord is already "in expectation" of her implies that he, like the speaker, is optimistic about the effect his message will have upon the lady.