endeavor, make effort, urge
勔 centers on applying force or pressure to drive action: endeavoring, making an effort, or urging someone forward.
勔 combines 面 (face) and 力 (power/force). The exact historical development is uncertain, but it likely expresses the idea of facing a task with force or urging someone face-to-face.
The left side 面 is a face, and the right side 力 is power. Imagine someone getting in your face and using their forceful presence to urge you to make an effort.
For ベン, picture a boss named Ben getting in your face and urging you to endeavor harder: Ben -> ベン.