var þat trúliga gört. GJ "but the job had been thoroughly done".
From the context, and maybe from the way the next sentence follows
on with no adversative conjunction, I assumed it refers to the
killing rather than the examination.

Moreover it can refer to the execution as well as the examination.

that was believably done: as one suspected.

Ambiguity that is the gist
of Icelandic tongue as we say it ambiguous.
Our ancestor stuffed the tongue with proverbs for the descendants so
they would be more orientated in distinguishing the measure (see
also syllables) in question.

If I lose my Job and take dole: Common people (before) would
say "umskipti" mér orðin. See Shift. Here the luck was shifted a
way from my. I'm not "object direct" but I'm "object indirect" in
the situation. Odds were not in favor. Goddesses extremely.

Thanks Uoden