The poem is built around a bitter irony. Someone tells the speaker they are afraid of losing them. That sounds like a promise to stay, or at least a sign of how much the speaker matters. But the next lines undo it: the person "faced your fears / and left." The very thing they said they dreaded is the thing they chose to do.
The twist is in the phrase "faced your fears." Normally that means being brave. Here it means walking away, which turns courage into something hollow and almost cruel. The speaker doesn't spell out their pain, but the flat, understated tone suggests hurt, confusion, and maybe a quiet kind of sarcasm.
The short lines and the sudden stop on "left" make the ending feel abrupt, like the speaker was caught off guard too. The mood is stark and heavy. Nothing is explained, and that silence is what stings. The title also hints that the real fear may belong to the speaker, who is now left without the person.