The poem starts with a flashback to the time when the speaker and his companion (most likely Thomas Hardy and his friend Florence Henniker) visited an inn together many years earlier. The first stanza sets the scene, and focuses on how the couple—who aren't actually a couple—were received by the staff and patrons of this inn.
The speaker and his female friend arrive together, though the purpose of the visit is never revealed to the reader. It's worth noting that for a man to be spending this kind of alone time with a woman who wasn't his wife would have been quite unusual during the strict moral atmosphere of the Victorian era (though plenty of illicit behavior still went on!). The speaker and his companion are "strangers" to the inn, and this anonymity, on the one hand, frees them from their identities. But this freedom is only in the eyes of others; if the poem is taken as autobiographical, both Hardy and Henniker were married to other people at the time. They are momentarily free to look like a couple, but not to actually be one.
Though they are "strangers," the staff at the inn feel happy to be in the presence of what they think is pure love. They offer their "catering care" to the newcomers, the prominent hard /c/ alliteration perhaps suggesting that the people at the inn are a little overbearing! Their smiles signal the vicarious happiness the staff feel as witnesses of this love, though they try not to make it too obvious.
The word choice that describes their attempts to hide their smiles—"veiled"—ironically gestures towards the wedding veil worn by brides. But as if demonstrating that this love is an illusion, the three alliterating /w/ sounds in line 4's "what we were" are showy and gaudy. Even just in these four lines, then, the poem sets up a tension between what people think about love and how, in reality, love can play cruel and deceiving tricks—between how things seem, and how things actually are.