Bright Star, would I were stedfast as thou art
How we cite our quotes:
No—yet still stedfast, still unchangeable,
Pillow'd upon my fair love's ripening breast (lines 9-10)
Well, now we get our answer: "No." Keats's speaker no longer feels loyalty for the star – or, at least, not totally. He wants to take the same eternal attention that the Star expends on scenes of cold, empty, barrenness, and transform them into loyalty for a human object.
To feel for ever its soft swell and fall,
Awake for ever in a sweet unrest (lines 11-12)
The repetition of the words "for ever" here seem to act out the eternity of the speaker's imagined loyalty for his girlfriend. The tenderness of the description, with its soft s and f sounds, and general warm and fuzzy feeling, helps explain why he would have such strong feelings of loyalty in the first place.
Still, still to hear her tender-taken breath,
And so live ever—or else swoon to death— (lines 13-14)
The beginning of the sonnet's couplet evokes some of the same feelings as the two lines that precede it. Here, once again, repetition is used to convey the eternity of the loyalty the speaker desires, and it also gives a sense of the emotional intensity of his desires. And yet, we get something new here too, something extreme. What is this? Well, if someone told you that they'd prefer to die if they couldn't spend the rest of eternity with their head resting on your chest, wouldn't you consider that a pretty extreme form of loyalty? It makes sense that this is the last line of the poem – you can't really take the theme any further from here. (That doesn't mean you shouldn't think about how to do it – if you come up with anything, why don't you try to write your own poem or song or whatever about it?)