What does Genesis 38:18 mean?

Judah said, 'What do you want from me?' She answered, 'Your seal, your cord, and the staff you’re carrying.' So he handed them over, slept with her, and she got pregnant by him. Genesis 38:18 - Modern Text Bible

(Judah, not recognizing Tamar, agrees to her terms and gives her his personal items as a guarantee. This sets up the proof of their encounter.)