We can make the meaning clearer by changing the word order and simplifying the structure. I'll add one more phrase of my own.
"Character is not the same thing as reputation. Reputation is only the echo of character. Reputation is often mistaken and misleading."
"Character" can mean integrity, moral strength, and honesty.
"Reputation" is what people think about someone. Someone has a good reputation if people admire him.
The unusual word order is used because the writer wants to talk about character, and wants to put the word "character" first. He is talking about the importance of character, and wants to make it clear that character and reputation are different things, and he thinks character is more important.
For example, Benedict Arnold was a distinguished general in the US Army during the American Revolution. The Revolution was fought by the United States against the British, and he was on the US side. He had a good reputation. But he secretly switched sides and betrayed the United States. He tried to surrender a fort to the British. So he had a good reputation, but actually had a bad character.
"Reputation is but the echo" means that people with a good reputation may have a good character, but it is just a "echo." An echo is the reflection of a sound, and it is often distorted. The writer is saying that reputation does reflect character to some extent, but it is only an "echo" and it can be distorted and misleading.
For example, Benedict Arnold's reputation was misleading.
(At least, that is what we think about Benedict Arnold in the United States! They may have a different opinion in the UK!)