What a crazy context for this excerpt. Clear example of the depth of anti-semitism during this time period.
It is "A Jew" telling a Christian boy where to go in England once he gets there. While the boy thinks the Jew is looking out for him, he is actually sending him to be butchered by the Jews in Winchester, which he characterizes as the most moral place in England after he goes on and on about the wretchedness of all the other places in England the boy might come upon. He gives the boy a note to show to the Jews in Winchester, "written in Hebrew" so the boy doesn't actually know what it says. Boy gets to Winchester and does as told, then soon disappears. Clearly he's been killed by the Jews, but why they had to go to so much trouble to get him to Winchester is unclear.
Oh... Right... That's because this is all made up by Christians desperate for reasons to get rid of Jews.