In the verses, the bass plays something like this:
(Note that the end of the third verse differs a bit as the song transitions into the coda.)
Under the title line (which occurs at the beginning of every verse), the bass begins by playing notes of all different pitches (G F# E), providing a hint of the entirety of "ev'ryone." In the third verse, this slight breadth gives a sense of the totality of "all" in the line "They all can see your love shine through" (the fifth and sixth measures).
"Still" in the line "Still ev'ryone's in love with you" (the third line of the first verse) could mean "nevertheless" or indicate an ongoing state. The constancy of the latter option is illustrated by the bass's repetition of the same phrase that it played under the similar line "Ev'ryone's in love with you."
The bass highlights the contrast in the lines "Ev'ryone's in love with you / But you can't fall in love with anyone" (the first two lines of the song) by going in opposite directions: descending under "Ev'ryone's in love with you," but ascending (albeit slightly) under "But you can't fall in love with anyone." This ascent even demonstrates the meaning of "can't fall" (if somewhat more literally).
Under the line "Though most just barely glimpse a part of you" in the second verse (measures three and four), the bass plays only two pitches spanning a small interval (a whole step), and this narrow scope matches the limitation mentioned in the lyrics.
