And will any say when my bell of quittance is heard in the gloom,
This is the first stanza since the first that does not open with "if." It starts with a question, instead.
The "bell of quittance" is the bell that is tolled at a church when someone dies.
The speaker imagines a kind of clichéd "gloom" around his own death – like if you're feeling angsty, and you imagine that whoever it was that you're angry at will at least feel sorry after you're dead.
And a crossing breeze cuts a pause in its out-rollings, Till they rise again, as they were a new bell's boom, "He hears it not now, but used to notice such things"?
The tolling of the bell that the speaker imagines is momentarily interrupted by a cross breeze.
The "out-rollings" refer to the sound of the bell, but it's a made-up word, and it sounds kind of like a wave on the ocean that might pull a swimmer "out" under the "rolling" waves.
After the brief interruption to the sound of the bell from the breeze, the "out-rollings" of the bell are heard again.
After the pause, it almost seems like a new bell.
The phrase "rise again" and the emphasis on "new bell's boom" suggests a possible hopeful note at the end of this gloomy poem – maybe there's a possibility of life after death for the poet? At least he might live on in the minds and memories of his neighbors? Maybe?
The final line is back to the doom and gloom: the speaker's friends and neighbors say to themselves that the speaker used to notice "such things," like the cool effect the wind had on the sound of the bell, but he's past caring about such things now.
Since the final stanza is one long sentence that is structured as a question, the entire poem ends with a question mark – perhaps inviting the reader to interpret it.