Hemiplegia, the paralysis of one side of the body, is a common side effect of stroke. This condition provides unique challenges for afflicted individuals, including asymmetric body strength and limited mobility, specifically in the stand-to-sit (StandTS) motion. Excessive impact forces in sitting and weight-bearing asymmetry are issues in the StandTS of hemiplegic individuals. In line with the UN SDG 3 on promoting good health and well-being, more accessible interventions to improve their mobility should be developed. The effectiveness of using a semi-wearable assistive robot to reduce impact forces and improve weight-bearing symmetry in StandTS is investigated. The assistive robot is a planar 2-DoF assistive robot attached to the hip of the user that provides a resistive force to slow the descending speed in StandTS. The assistive robot also restricts pelvic translation in the frontal plane to promote increased loading on the non-affected leg. Proof-of-concept experiments on healthy test subjects showed that the assistive robot could significantly reduce sitting impact forces and improve weight-bearing asymmetry in the StandTS motion.