Heath Ledger joker's classic lines in "The Dark Knight" are as follows:

1. Sometimes, I laugh so hard that I cry when I laugh, feeling pathetic. It's ridiculous, just smiling like this, smiling like a clown, like a fool.

2. We are like clowns, spending every day laughing and joking. Even if we shed tears, others will think that there is sand in our eyes.

3. I feel like a clown, being laughed at by others.

4. No one has ever known the clown’s heart. In fact, when I usually watch clown performances, I feel very disappointed.

5. What is it like? After knowing that I have been deceived and betrayed, my personality and self-esteem have been trampled to the ground, and I have become a clown again.

6. In fact, when I usually watch clown performances, I feel very disappointed.