Any statement can follow bahwa “that”.
A bahwa clause is an object of a transitive verb or as complement of an intransitive verb.

Examples:
Anda menjawab, “John tidak percaya kabar itu.” You replied,” John doesn’t believe that news.”
Anda menjawab bahwa John tidak percaya kabar itu. You replied that John didn’t believe that news.

Bahwa clauses most frequently occur as objects or complements of verbs which report something that happened.

Examples:
Dia sadar bahwa dia telah pensiun. He was aware that he had been retired.
Mereka percaya bahwa mereka dapat mengatasi kesulitan ini. They believe that they can overcome this difficulty.

The intransitive verbs which can have a bahwa clause as complement:
tahu know berkata say
percaya believe berpendapat have the opinion
ingat remember beranggapan have the opinion, consider
sadar be aware berpikir think
lupa forget

When a bahwa clause is object or complement of intransitive verbs, bahwa can be omitted.

Examples:
Saya tahu (bahwa) dia sakit. I know (that) he is sick.
Guru berkata (bahwa) pelajar-pelajar harus belajar keras. The teacher said (that) the students must study hard.

If the subject of the bahwa clause the same as the subject of the main clause, it can be omitted along with bahwa:

Examples:
Mereka berjanji bahwa mereka akan memberi hotel yang terbaik. They promised that they will provide the best hotel.
Mereka berjanji akan memberi hotel yang terbaik. They promised to provide the best hotel.