Her words were aptly chosen to comfort her friend without seeming forced.

aptly 是形容词 apt（恰当的）加上副词后缀 -ly 构成的副词形式，意思是"恰当地、合适地"。apt 本身就有"恰当的、贴切的"含义，加上 -ly 后表示以这种方式进行。