Learn Romanian: Băiatul te așteaptă la bar. - The boy is waiting for you at the bar.

In English, you wait for someone, but the Romanian verb a aștepta takes a direct object. This means the action is done directly to the person being waited on. That is why we use the direct object pronoun te right before the verb, with no extra preposition needed.

Why does the sentence use la bar instead of în bar?

Using la (at) treats the bar as a general venue or meeting place, which is the most natural choice when you are meeting someone. If you used în bar, it would specifically emphasize the fact that the boy is physically inside the room or building.

If I wanted to emphasize that he is waiting for YOU (and not someone else), how would this sentence change?

You would add the stressed pronoun pe tine after the verb, making it: Băiatul te așteaptă pe tine la bar. Notice that you must still keep the unstressed pronoun te before the verb. This double-pronoun rule is required in Romanian when emphasizing a specific person as a direct object.