We met in our favourite pub, we kissed each other passionately like the first time, and then we sat down.

passionately 是形容词 passionate 的副词形式，由 passion（激情）加后缀 -ate 构成形容词，再加 -ly 变成副词。passionately 表示"充满激情地、热烈地"，描述动作的方式。