Plug connector and connector assembly

The plug connector includes: a connector body including a pair of first side walls extending in a first direction and facing each other and a pair of second side walls extending in a second direction perpendicular to the first direction and facing each other; a pair of mounting pins coupled to the connector body; and a plurality of plug terminals coupled to the pair of second side walls. Each of the pair of mounting pins includes: an upper surface contacting an upper end of the first sidewall; a central reinforcement bent downward from the upper surface to contact at least a portion of an outer surface of the first sidewall; and a pair of side reinforcing portions extending from both ends of the upper surface in the second direction to contact an upper end of the second side wall. The central reinforcement includes a central weld extending downwardly from a lower end of the central reinforcement and surrounding at least a portion of a lower surface of the first sidewall. Each of the pair of side reinforcing p