关于那个未实现旳诺言。 英语怎么说，谢了。

没有实现的，用定语从句比较服从外国人说英语的习惯。
About the promise which has not been fulfilled

或者把fulfilled换成lived up to

BS用软件翻译的，错误百出，不对他人负责任！！

about that promise which hasn't been implemented

about that unfulfilled promise

about that unachievable promise

What I did not realize the undertaking of promise

1楼的好