The two missionaries responded in the way that one stood his ground while the other thought it to be fruitless to try.
Explanation:
In these chapters of the book, Okonkwo the protagonist of the work and an Igbo chief of some importance had decided that he will oppose the influence of these missionaries over the land he is of.
Thus, his struggle begins against their influence and he is able to say to them that they must leave the village.
One of the missionaries gets scared of by this insistence but the other is able to stand his ground against the insolence he believes it to be and thus he is able to see the wrath of Okonkwo on himself.
A prepositional phrase needs to contain a preposition, in this case it would be "between". As well it needs to modify the sentence and it should mention the object of the sentence. So "between the two countries" is correct.
