I can afford to speak frankly.

我可以坦率地说。

Lucy: Do you mind if I speak frankly?

露西：我实话实说您介意吗？

Always speak frankly.

我们总是坦诚相见。

I feel it my duty to speak frankly to you.

我觉得我有义务要坦白地对你说。

To speak frankly, it doesn't depend on me.

坦白地说，这不是我能决定的。