Depends of the context. I believe you mean to say welcome to..., that is Bine ai venit(sg) or Bine aţi venit (pl)

The answer is relative .. it can either be : - a saluta - I welcome this decision. - a întâmpina - I welcome the opportunity However i think you wanted to say something in the lines of this : Welcome to Romania - bine ati/ai venit in Romania ! Welcome everybody - bun venit tuturor ! / bine ati venit !

welcome - BINE AI VENIT or BINE ATI VENIT or BUN VENIT