Thanks to everyone who replied.

Now I have a question about usage. I'd like to know which of the following sentences you find acceptable, and which you don't. There may be different usage in different English speaking countries, so please include your nationality.

1. a) He convinced me he was sincere.
b) He convinced me that he was sincere.

2 a) He persuaded me he was taking the right course of action.
b) He persuaded me that he was taking the right course of action.

3 a) He reminded me I had to post the letter.
b) He reminded me that I had to post the letter.

4 a) He told me he had to go.
b) He told me that he had to go.

5 a) He warned me the roads were dangerous.
b) He warned me that the roads were dangerous.

6 a) He realised it was already too late.
b) He realised that it was already too late.

7 a) He said he was sorry.
b) He said that he was sorry.

8 a) He suspected John was a thief.
b) He suspected that John was a thief.

9 a) He promised he wouldn’t be long.
b) He promised that he wouldn’t be long.

10 a) He promised us he wouldn’t be long.
b) He promised us that he wouldn’t be long.

11 a) He complained the soup was cold.
b) He complained that the soup was cold.

12 a) He explained the waiter had a lot of tables to serve.
b) He explained that the waiter had a lot of tables to serve.

13 a) He suggested the restaurant should employ more waiters.
b) He suggested that the restaurant should employ more waiters.

14 a) He wrote he wasn’t satisfied with the service.
b) He wrote that he wasn’t satisfied with the service.