en_tn_lite_do_not_use/deu/22/28.md

but who is not betrothed

"but whose parents have not promised another man that she will marry him"

lies with her

This is a euphemism. Alternate translation: "has sexual relations with her" (See: rc://en/ta/man/jit/figs-euphemism)

if they are discovered

This can be stated in active form. Alternate translation: "if somebody finds out what happened" (See: rc://en/ta/man/jit/figs-activepassive)