Answer:
“because your laughter / will be for my hands / like a fresh sword.”
Step-by-step explanation:
Metaphor is a figure of language in which one uses a word or an expression in a sense that is not very common, revealing a relation of similarity between two terms.
In this case, the author of the phrase is establishing a relationship of resemblance between a smile and a sword. He meant that the smile of his beloved makes him powerful in the same way that a sword would leave.