Speaking as "we," the speaker points out how big our promises are and how small our actions turn out to be. We claim we would do anything for the people we love, but we refuse when asked. We swear we would hold on until our last dawn, then drop everything for a tempting opportunity without a backward glance. We say we love them, yet a petty argument leaves us sulking in silence, refusing to forgive.
The tone is blunt and self-accusing, almost like a confession. Using "we" makes the reader part of the guilt rather than a bystander. The poem's final stanza softens things. We believed we were honest and kind, and only noticed dishonesty when we saw it in others. The closing thought, that perhaps they lied too, suggests that everyone fails. Still, the speaker ends on a hopeful note: a world where nobody cared or loved would be far worse, so the effort to care still matters.