걱정되는 is a present modifier conjugation of 걱정되다. 걱정하는 is a present modifier conjugation of 걱정하다. Generally, N+하다 is an active verb(능동사) and transitive verb(타동사) and N+되다 is a passive verb(피동사) and intransitive verb(자동사) 걱정하다 is active verb and transitive verb 걱정되다 is passive verb and intransitive verb 나는 그를 걱정한다. <=> 나는 그가 걱정된다. If it is used without an object or a subject, it can be used interchangeably 가장 걱정하는 일 = 가장 걱정되는 일 The nuance of a passive verb is more humble than an active verb. Here is an explanation of 기대하다 and 기대되다. 기대하다 is an active verb(능동사) and 기대되다 is a passive verb(피동사) An active verb is a verb which describes an action by a subject with the intention of the subject. It is used with an object. A passive verb is a verb which describes an action by other person. It is used with a subject. 저 선수의 장래가 기대된다. = 저 선수의 장래를 기대한다. The future of that athlete is expected = I expect the future of that athlete. If it is used without an object or a subject, it can be used interchangeably 가장 기대하는 일 = 가장 기대되는 일 The nuance of a passive verb is more humble than an active verb. You can use 기대되다 in formal situation. You can use 기대하다 in informal situation.