I'm bound to say that I have some doubts.

我有责任告诉大家我有些疑问。

Sometimes, I'm bound to say, they are in a hopeless muddle.

有时候，我只能说他们糊涂透顶了！

The captain has said too much or he has said too little, and I'm bound to say that I require an explanation of his words.

船长是说得太多了，或者他说得还远不够，而我必须要求他解释一下他的话。