I've been pondering (though these are just my thoughts, no one has to agree, and I always encourage feedback
). This thread may be able to explain why Faramir was able to resist the Ring and Boromir wasn't. I think there's many things that go into Faramir being able to resist, but all and all, it's been sort of an uknown/opinionated topic. Numenorean blood ran truer in him, he was wiser in lore, he learned from his brother's mistakes...etc, while I think these all contribute to Faramir being able to resist the Ring, I think there's something missing, and this thread may have just explained it. I mean Faramir doesn't even show signs of being severely tempted, he comes and flat out denies it.
I think it lies with the important phrase of Faramir's..."Not if Minas Tirith were burning to the ground would I use it."
Now, this I don't think shows that Faramir could give a rat's behind about Gondor, but I think it's just Faramir accepting he can't control what happens. As being discussed, there's a higher power at work, and accepting that you can't be in control is a key to spiritual healing.
The Ring is all about control and controlling what happens. Faramir realizes that he's not in control, and that he can't control what happens (nor does he want to control what happens) hence his fond denial of the Ring.
Where his brother wants to be in control of what happens and his strong pull to the Ring is because he wants to be in control. Where Faramir's strong resistance to the Ring comes from his unwillingness, and KNOWING the he can't control. It's not up to him.