Why did she [initially] not believe?
Malbim: (a) [Normally,] one who engages in intellectual investigation does not know how to run matters in practice. (b) She could not believe that his heart (Chachmah) is so encompassing.
Why did she say "I was not told half"?
Malbim: Natural Chachmah has a limit. The renown of a distant Chacham is greater than that of a close one, for people see that his Chachmah is limited and he does not know everything, and his knowledge is not clear. Shlomo's Chachmah was Divine, like a spring that flows from a Divine source and constantly increases.
What are "Chachmah va'Tov"?
Malbim: They are intellect and good conduct, respectively.
Why did she say "El ha'Shemu'ah"?
Ralbag #1: This is like li'Shemu'ah. What I saw of your Chachmah joins to what I heard.
Ralbag #2: This is like Al ha'Shemu'ah.