Did Melech Ashur have a particular land in mind?
Rashi: No. After I find a land like yours, I will exile you to there. This is my practice - "v'Asir Gevulos Amim" (10:13).
Rashi (Melachim II, 18:32): He would exile them to Africa 1 .
Malbim: Yes. Refer to 36:17:3:2.
One opinion in Sanhedrin 94a says that this is where he exiled the 10 tribes. I do not know Rashi's source that he intended to exile Yehudah to the same place. (PF)
Why did he promise them a land like their land?
Rashi citing R. Shimon (Sifri Ekev 37): Was he a fool, who did not know how to entice 1 ?! Rather, he could not find anything derogatory about Eretz Yisrael.
Rashi (Melachim II, 18:32 from Sanhedrin 94a): He was wise. Had he promised them a better land, they would know that he lies.
Sanhedrin 94a: He was a fool! Surely, people will not agree to move unless they think that the new land will be better 2 !
Why did he say both "a land of grain and wine" and "a land of bread and vineyards"?
Radak (Melachim II, 18:32): Do not think that the grain and wine come from other cities. The land itself produces them.
Malbim: Do not say that the new land is desolate, and before you can plow, plant and reap, you will starve. The grain and grapes are standing, and bread is prepared. I exiled its inhabitants when their vineyards were planted and their grain was grown.
Why will he exile them?
This is my practice - "v'Asir Gevulos Amim" (10:13). Radak (Melachim II, 18:32) - all nations that he conquered, he exiled them and put others in place of them, so all would be conquered under him. Also Yosef did so to the Egyptians - "v'Es ha'Am He'evir Oso le'Arim" (Bereishis 47:21).