Another mistranslation

[HerenIstarion]

Correct. Compare it now with the original heh:

You knew it very well, I deem! How can you tell me you did not know that your behavior is stupid and foolish? You knew it, and kept telling the truth to yourself, yet did not obey your own wisdom. And I did not warn you, for truly nothing was clear until now, but even if I was to warn you, you would not listen to me, but perform your foolishness even more eagerly. And now, having burn your tongue on a hot milk, you will be wary with a cold water, and will lend your ears to good advice

'Oh yes, you had,' said Gandalf. 'You knew you were behaving wrongly and foolishly; and you told yourself so, though you did not listen. I did not tell you all this before, because it is only by musing on all that has happened that I have at last understood, even as we ride together. But if I had spoken sooner, it would not have lessened your desire, or made it easier to resist. On the contrary! No, the burned hand teaches best. After that advice about fire goes to the heart