Why does Frodo have to fly solo without the others at the end of The Fellowship of the Ring? Especially Aragorn and Legolas both seem like incredible assassins/bodyguards and basically immune to the draw of the ring.
Frodo saw the effect the ring had on Boromir (Sean Bean), and knew that eventually it would corrupt the rest of the Fellowship. No one is immune to the ring. Even, Gandalf and Galadriel refused to touch it. Frodo as a hobbit, is a bit resistant to the ring, but not completely impervious to it's influence. This is something that Lady Galadriel had foretold (emphasis mine).
So Frodo knew that if he was to have a real chance at destroying the ring he would need to do this by himself and carry the burden alone. Of course Sam had other ideas.