1)
What is the meaning of "Lo Nasog Achor Libenu"?
1.
Radak: Our heart did not retract from Emunah in You.
2.
Malbim: Refer to 44:19:3:2.
2)
What are "Ashureinu"?
1.
Metzudas Tziyon: They are our steps.
3)
Did our steps veer from Hashem's ways?
1.
Radak: No; "Lo" applies also to this.
2.
Malbim: Yes; sometimes due to the heavy [yoke] of Galus, we were not able to fulfill Mitzvos properly. Even then, our hearts did not retract; they are complete with Hashem.