Well, I think the Ring is an "universal-most-evil-thing-trying-to-use-what-best-ways-it-could-to-break-down-the-bearer". You know, it is that kind of thing which would say "I will make you smart enough to rule the market in this city" to a businessman or "I will get you enough power to become a president" to a candidate, or "I will help you to pass the exams" to a student. It plays on the highest desires of the bearer. In Frodo's case, however, it seems that there is no particular reason. Maybe this is just why Frodo was the best for bearing it - he had no hidden desires. The only desire of Frodo I can think of is, to be peace&quiet, the best somewhere in Rivendell with Bilbo. But still it was not so strong desire. In the barrow, the Ring wanted Frodo to put it on under cover of escape. But after having the experience, maybe the Ring knew that Frodo wouldn't put it on out of this reason --- or, and I think, in this particular case (at Weathertop), much like later in Morgul and other times, Frodo put it on just because of the evil will of the Ring (maybe combined with the will of the Nazgul) - just an order: NOW PUT ME ON! There was no temptation behind it: both Frodo and the Ring knew what the other represents, Frodo knew the Ring is evil
and had no desire of letting the evil happen, he wouldn't have gained
anything from it. There was just that supernatural force, evil will, at that time.
Concerning this point, to enlighten if Frodo actually did have any reasons why put the Ring on, I would mention two other occassions:
1) under the gaze of Galadriel (where, if you remember, everyone of the Company felt as if he's being offered something he desired very much). I'd call this occassion "Galadriel's mind probe aka The One Ring Lite". It was just a test - and also I think just a
taste - of what would the Ring offer to the Companions. Frodo was also offered something, as much as anyone else - and I think, this, in his case, was something like "you could return to the Shire and rest there for the rest of your life, no Rings, no rushes". (Note: consider, that if you were the Ring, you'd probably have a hard time to operate with this "lure". The best you could achieve would probably be to get yourself tossed or passed to someone else - which is not so bad, after all, as the next person would probably have more faults than Frodo.)
2) The second, more important. Mount Doom. This is more of a problem. I don't think Frodo here just took the Ring because it finally persuaded him that he could return safely home if he takes it on. I also don't think he took it on because he was exhausted and the Ring finally broke his will in "just put me on" like on Weathertop with no other reason for taking it on. The best reason I can think of is "a blackout of mind" (or "a momentary lapse of reason"
), when all the evil will and pressure and exhaustion actually persuaded Frodo that he
of course wants to take the Ring, not to destroy it, and left no place for reasoning. That's all I might have to add, thus far. I'll try to think about it yet.