Factbox: Singapore to Hanoi - The bumpy diplomatic road since Trump and Kim first met

FILE PHOTO: U.S. President Donald Trump and North Korea's leader Kim Jong Un walk together before their working lunch during their summit at the Capella Hotel on the resort island of Sentosa, Singapore June 12, 2018. REUTERS/Jonathan Ernst

SEOUL/WASHINGTON (Reuters) - It's been the better part of a year since U.S. President Donald Trump and North Korean leader Kim Jong Un stood face to face for the first time at their unprecedented summit in Singapore.

As the two leaders prepare to meet in Vietnam for a second summit, there is a growing expectation that this time they need to make a more specific agreement.