Aragorn's reluctancy, was it totally wrong?

[Lathriel]

I liked the way Aragorn was portrayed in the movies. They could also have gone for a macho portrayal of Aragorn and that would have been much worse since that would have completely gone away from the book.
Even when I read the book for the first time I sensed a great amount of reluctance in Aragorn.
As for

“I will not bring the RING to within a hundred LEAGUES of your city!”

I think Aragorn says this because he fears what will happen if the ring gets to Gondor. He probably also recognized the fact that Boromir was drawn by the ring and knew that the same could happen to the citizens of Minas Tirith. Most imporantly the Steward.