1)
What will cause them to repent?
1.
Rashi: When the nations will see the good, they will remember the evil that befell us, and they will repent to Hashem. Also refer to 21:30:1:1.
2.
Radak: The nations will remember the poverty that Yisrael had in Galus, and see the great salvation.
3.
Malbim: They will remember what I say to them (that Meluchah is to Hashem - refer to 21:29:1:1).
2)
Why will they bow to him?
1.
Malbim: It is because he is Moshel over nations (verse 29). He has the power to punish and destroy nations and kingdoms. They will bow Bal Korcham (against their will), amidst fear.
