After his summit with Kim in Singapore on June 12, Trump said he was told by Kim that the North was "already destroying a major missile engine testing site" without identifying which site. The leaders concluded their summit by declaring their vague aspirational goal of moving toward a nuclear-free Korean Peninsula, but there's lingering doubts on whether Kim would ever agree to fully give up the nuclear weapons that he may see as a stronger guarantee of his survival than whatever security assurances the United States can provide.