求翻译：一直固执的以为面对什么事情我都能够坦然的微笑，可是，终于在你转身决定离去的一刹那，我泪如泉涌，不可抑制。这是，过往的幸福嘲笑着心中的疼痛，原来，世界上最痛的痛是离开。是什么意思？

What has been thought in the face of stubborn I can frankly smile, however, leave you decided at last moment I aren ' t over flowing steadily, not inhibit. This is, happy laugh at pain in the heart of the past, the original, the world's pain is the pain of leaving.