Florid and romantic—(small &#8216;r&#8217;)—language suffuses the poem, &#8220;Bright Star,&#8221; by John Keats, filling it with a sustained emotional urgency, but masking perhaps the truth that&#8217;s laid bare in the opening line—that the speaker feels himself not to be &#8216;stedfast,&#8217; at least, not so steadfast as a single star, perhaps Sirius, in the nighttime sky. The poet could wish his love and affection to be eternal, unwavering, ever-generous and vigilant, and that when the time should come for his love to expire—with the end of his life, presumably— he will, like the collapse of a star, &#8220;swoon to death.&#8221;
Fundamentally, the poem is an assertion of strident feelings, and a wish to stake a claim to enduring commitment. What draws this into focus is a matter of scale: we&#8217;re given a lovely description of this single bright star as a kind of care-taker or guardian angel of the earth. This is set against the young man, presumably looking down &#8220;Pillow&#8217;d upon&#8221; the object of his love not only with the ardency of his acute passion, but with a kind of spiritual affection and sense of soulful communion.  However, unlike in a religious ceremony such as a wedding(and religion is evoked explicitly by the poet in the use of the word &#8220;Eremite,&#8221; described below), the poet&#8217;s cogent statement is not a lasting testament to love&#8217;s faithful vows.
The first line&#8217;s use of the word &#8220;would&#8221; ushers in the all-important conditional tense, immediately creating an environment of doubt or insecurity, no matter how bravura the statements that will follow, and suggesting that there are conditions that need to be met in the present moment in order for the speaker to step into the role of &#8216;Bright Star,&#8217; technically impossible, as a mere human, though that may be. But as the poem stands, these conditions form the secret mystery of the poem: regarding what these conditions are and how they might be met, and whether they are hypothetical and contingent, or pressing and actual, the poet remains haltingly silent.
It&#8217;s the statement of a moment, a truth that is real in an instant, and memorialized in poetry. In that way, Sonnet 18 by William Shakespeare (whom Keats revered) is brought to mind, whose conclusive lines are:
<div>   So long as men can breathe or eyes can see,</div>
<div>   So long lives this, and this gives life to thee.</div>
These words reflect a key part of the sentiment in Keats&#8217; poem. Namely, that no matter how evanescent a love might be, there is an aspect of the eternal in its piquancy and power, and if that sentiment is properly captured in poetic language, that love does indeed have a chance to endure for the ages.
No matter what, &#8220;Bright Star&#8221; contains breathtakingly beautiful verse, and perhaps suggest, under its rather rococo exterior and form, that the truth of making of love-match is not a matter of universal vigilance, and rather an issue of the small, interpersonal relationship-building that a lasting love might be built upon, certain  commitments made in the heat of passion notwithstanding.
Happy Reading!
-Allen Guy Wilcox
P.S. Eremite means &#8220;hermit&#8221; — in this case with Christian overtones.