In the movie LOTR: The Fellowship of the Ring, I am wondering why Frodo didn't tell Aragorn, or one of the others in the fellowship, that Galadriel had told him that Boromir would try to take the One Ring. I would think that Frodo would want them to know this so that they could keep a constant watch over him while the group traveled on to Mordor.
Why didn't Frodo tell the others that Boromir would try to take the One Ring?
In both the movies and the books it is clear that the Ring is semi-sentient and has “wants”: the primary one being that it wants to return to Sauron. Or, perhaps more accurately, it responds to Sauron’s desire to regain it. More speculatively, it “wants” to be wielded by someone with the power to do so.
Boromir was more likely to fulfil both “wants” than Frodo. The Ring has a history of discarding bearers when they no longer suit it. It abandoned both Isuldur and Gollum - it might have been waiting for an opportunity to abandon Frodo. Indeed, it had already done so in the Misty Mountains, slipping free of Frodo right in the path of Boromir.
Also, the ring makes its bearer bat-shit crazy and paranoid.
Galadriel only says "he", not "Boromir".
Does Boromir want it? Sure, we've seen that when the Ring "falls" into the snow in the Misty Mountains.
How about Aragorn though? The reason the scene with Frodo and Aragorn at the Breaking of the Fellowship is so powerful is because up to that point we don't know. Up to that point, Boromir has always been the one who's been closer to the hobbits (especially Merry and Pippin), and Aragorn has been quite standoffish with them. He's been a good leader, but not necessarily likeable. We also know that Aragorn is afraid he'll be tempted the same way his great-however-many-grandfather was - so not only do we not know, but the character doesn't know either.
The story of the Fellowship film isn't just character development for the hobbits. Jackson also managed to build in character development for Aragorn, Legolas and Gimli, something which is famously absent from the book. Remember that the book itself was a loving pastiche of Norse sagas. Jackson knew that he had to produce something which would stand up to modern standards of story-telling. Aragorn facing down that temptation is the point where he rises to be better than Isildur. Everything afterwards is detail - exciting detail, to be sure, but closing Frodo's hand back over the Ring is when he earns the right to be king, and Boromir says as much as he dies.
And the "he" could also be Sam, or even Merry or Pippin. Frodo is already getting the effects of the Ring by that point. Pippin proves his own weakness later with the palantir, after all. Sam has to virtually drown to prove himself to Frodo.
There's no shortage of "he"s, basically.
Frodo tries to see the best in people; when Boromir then acts on it, Frodo again allows him a final dignity of silence.
