The speaker implies that had they known from the outset that their entire life would depend on trust, they would have found it impossible to live.

This couplet beautifully captures a profound truth about life. It suggests that if we truly knew from the very start how much our entire lives would depend on trust – trust in people, in circumstances, in the future – we might not have had the courage to live at all. It's a gentle reminder that we often navigate life by placing our faith in things unseen or unproven, and perhaps that's a necessary innocence. This reliance on trust, though sometimes risky, is what allows us to move forward, to build connections, and to experience life fully, even if it means stepping into the unknown with an open heart.