North Korean leader Kim Jong Un still has faith in U.S. President Donald Trump’s commitment to ending their nations’ hostile relations, but he’s frustrated by questions about his willingness to denuclearize and wants his “goodwill measures” to be met in kind, South Korean officials said Thursday. The trove of comments from Kim, including his commitment to a nuclear-free Korean Peninsula and to the suspension of all future long-range missile tests, were relayed by top South Korean security officials returning from meeting him in Pyongyang as well as by the North’s propaganda specialists. Even in their indirect form, each statement will...