Why was Jim no longer suspicious of Long John Silver after their first meeting?

Silver didn't look like the buccaneer (pirate) he expected.... Silver was congenial, clean, and well mannered. He also admits to knowing the men Jim is frightened of, and lastly, he has a great sense of humor. In addition, he confesses his knowldge of all these men to the Squire and the Doctor. He boards the ship with a clean, if untruthful, slate.

Now, to tell you the truth, from the very first mention of Long John in Squire Trelawney's letter I had taken a fear in my mind that he might prove to be the very one-legged sailor whom I had watched for so long at the old Benbow. But one look at the man before me was enough. I had seen the captain, and Black Dog, and the blind man, Pew, and I thought I knew what a buccaneer was like—a very different creature, according to me, from this clean and pleasant-tempered landlord.