What is "b'Chol Zos"?
Rashi: They saw the ruinous punishment of their colleague (Yisrael).
Malbim: Yehudah was unlike Yisrael, which never repented. After each Zenus, she returned to her husband's house like a Kosher woman, but it was not sincere.
What is the grammatical form of "Bagodah"?
Radak: It is an adjective. Normally, there should be a Sheva under the first letter, like Kerovah and Rechokah.
Why does it say "Ki Im b'Sheker"?
Rashi (from Eichah Rabah 1:18): The generation of Yoshiyah showed themselves to be Tzadikim, but they were Resha'im. They made images of idolatry on the inside of the doors, half on each door. When [the king's] Sheluchim checked for idolatry, the door was open, and they did not recognize the image.
Malbim: Her heart leaned towards idolatry.