WASHINGTON — Ukraine’s new ambassador to the US said Kyiv and Washington “understand each other much better” with President Trump in the White House — and is optimistic that an end to the bloody war could soon be a reality. In her first interview since taking office, Amb. Olha Stefanishyna told The Post that Kyiv now has a clear plan to end the war with Russia after months of dogged behind-the-scenes coordination with the Trump administration. “After all of these months of discussions, we know