Bewear is good but not spectacular for an in-game playthrough. Its high HP and acceptable Defense make it a passable physical tank (especially if it comes with the Ability Fluffy), while its robust Attack stat and Fighting STAB let it dish out more damage than it takes. It falls short with its Special Defense and Speed. It will crumble to just about any Psychic or Fairy move -- and its 60 Speed means it'll often have to take an attack before hitting back.
One of Bewear's Abilities is Klutz, an often worse-than-useless quality that means it can't use any items in battle. Its other standard Ability is Fluffy, which is much better (provided you keep Bewear away from Fire moves). This is because, as mentioned, halving damange from contact moves lets Bewear serve as a capable physical wall. Always try to catch a Stufful with Fluffy instead of Klutz.
If you want to use Bewear in-game, a good moveset would probably look like:
Bewear
Ability: Fluffy
- Return (Malie City)
- Brick Break (TM in Verdant Cavern)
- Shadow Claw (Konikoni City TM Shop)
- Rock Slide (Melemele Sea with Sharpedo Jet)