1)
What is "Emunasi v'Chasdi Imo"?
1.
Radak: Chesed was choosing him to be king. Emunah is fulfilling His promise, that he and his seed will be king forever.
2.
Malbim: Emunah is what I do for him based on his deeds; Chesed is what I do for him because I chose him, and not based on his merit.
2)
Why does it say "uvi'Shmi"?
1.
Radak: When he mentions My name, I will help him.
2.
Malbim: Since all will know that My Hashgachah is over him, My name will raise his horn; they will see that My name is called on him, and they will fear him.