A requirement is a formal statement of a desired result (a real world effect) that, if achieved, will satisfy a need.
As it is written, a RWE may be read as the desired result. However, requirement likely targets the result AND, optionally, shared RWE, and may have no clue about shareable RWE.
Proposed:
A requirement is a formal statement of a desired result (and, additionally, a real world effect) that, if achieved, will satisfy a need.