I have a question about the translation of this sentence from uncle Vernon in Harry Potter and the Philosopher's Stone:
Original Japanese: "あいつらは身から出た錆、魔法使いなんて変な仲間と交わるからだ …思ったとおり、常々ろくな死に方はせんと思っておったわ"
My translation: "They got what they deserved, because they got involved with those 'wizard' weirdos...Just as I thought, I thought there isn't always/usually a good/decent/satisfactory way of dying."
Published English translation: "Just what I expected, always knew they'd come to a sticky end."
I don't quite understand how the text in bold comes together here to form the intended meaning. I'm not looking for a smooth translation, rather just trying to grasp how the Japanese comes together here.
Many thanks in advance.