How can a person endure the hardships of love when they mistake its very beginning for the end?

This couplet captures the sheer magnitude of love's trials with a gentle, knowing smile. The poet muses on the naive lover who breaks down at the very first pang of heartbreak, mistakenly believing they have experienced the worst of it. If someone takes the mere threshold of love to be its ultimate boundary, how could they ever survive the devastating storms that are yet to come?