Two sp3 (tetrahedral) carbons are created at this stage, which allows two different  diastereomeric possibilities of the halohydrin intermediate. The most likely result is due to chemical kinetics: whichever product is easier and faster to form will be the major product of this reaction. The subsequent SN2 reaction step proceeds with stereochemical inversion, so the cis or trans form of the epoxide is controlled by the kinetics of an intermediate step.
Two sp3 (tetrahedral) carbons are generated at this stage, resulting in two distinct diastereomeric possibilities of the halohydrin intermediate. The most probable outcome is due to chemical kinetics: the product that forms more easily and quickly will be the major product of this reaction. The subsequent SN2 reaction step proceeds with stereochemical inversion, so the cis or trans form of the epoxide is controlled by the kinetics of an intermediate step.