"I don't think they are going to negotiate it away", Grinius said.
The Vancouver meeting is expected to put a heavy emphasis on finding ways to crack down on the many smuggling and money-laundering schemes that Pyongyang has employed to sidestep sanctions and pay for its nuclear program.
Trump has repeatedly insulted the North Korean leader, describing him as mad and a "rocket man".
Trump suggested his variable position on individuals was part of a broader strategy.
One of the options to be discussed, he said, would be naval interdiction to stop North Korean smuggling. All parties should work to defuse tensions and promote dialogue, rather than blindly resort to pressure and isolation.
But Hook said the idea was one of many being explored, and that the allies invited to Vancouver would be consulted.
He also said that China would continue to make its own efforts to push the peninsula nuclear issue back to the track of dialogue and consultation as well as settlement.
"And maritime interdiction helps us to disrupt resources and then the financial side helps us to disrupt the financing of their nuclear and missile program".
The countries invited to send representatives to Vancouver are the so-called "Sending Powers", those that contributed troops or aid to the United Nations war effort in 1950s Korea.
However, some key players will not participate in the event: North Korea itself, as well as Russian Federation and China, which are opposing the event, urging the sides of the conflict to engage in talks and stop actions, which might potentially escalate it (proposing so-called "double-freeze" plan).
But Hook said Washington remained in contact with China about enforcing the sanctions and pressuring Kim, and that both Beijing and Moscow would be briefed after the talks.
"We believe that only in this format, at the negotiating table, in a calm and normal atmosphere this very complex problem can and should be solved", Zakharova said, ruling out any possibility of a military option. "This is not an alternative to everything that we are doing". "This ministerial will enhance and strengthen all of the efforts underway to achieve our policy goals".
"In terms of how big of an impact it (falling trade) had on North Korea, there was definitely impact because some of their products could only go to China while others could only be imported from China", said Chen Fengying, an economics expert at state-backed China Institutes of Contemporary International Relations.