1)
Why does it say "va'Tavo El Chamosah"?
1.
Malbim: He accompanied her (refer to 3:15:2:1) only until the city. Then, they separated - he went to the city alone, and she went to her mother-in-law.
2)
Did Na'ami not recognize Rus?
1.
Torah Temimah citing Rus Rabah 7:4: She asked, are you [still] single, or married?
2.
Malbim: It was still [so dark] that one could not recognize his colleague.
3)
What is "Kol Asher Asah Lah ha'Ish"?
1.
Malbim: He swore to her that she will be redeemed, via Tov or via himself.