His intelligence chiefs warn that North Korea is unlikely to surrender its nuclear weapons. His advisers fret that a breakthrough could prove elusive and that he might make an impulsive concession to score headlines. And his allies around the world worry he could get easily outmaneuvered.

Yet, President Trump is steadfast in his determination to meet face-to-face here this week with Kim Jong Un, aides say, because he has an unwavering faith in the power of the pen-pal relationship he has cultivated with the North Korean leader not only to bend the course of history, but to shape his own legacy.