Very, true, and sooth show that when a word means “true” and it’s used a lot, you can almost predict that, over time, it will glide from meaning “truth” into meaning “very.”
The Vikings settled and coped with English, and all indications are that Old Norse in England lasted not much longer than the first generation of invaders. History records no enclaves in England where Old Norse was spoken for generations after the invasions. The Vikings spread themselves out, and wherever an Orm Gamalson settled down, what was spoken was English—and Orm’s children likely had the same orientation toward Old Norse as Jewish immigrants’ children in America in the twentieth century had toward Yiddish. Old Norse was the Old Country; English was the native tongue—cool, in a word.