Is there a forum where I can introduce myself without it being spam?

General chat, but be prepaird to get spamming alot about being a multi http://forums.d2jsp.org/forum.php?f=27

What's that?

Its general chat.. your in general help right now, general chats for spam and off topic stuff. Like selling guilds and tlkaing about nonsince getting +1's for your post count.

What's a multi? Is it offensive? :/

Don't worry, a multi is one person with multiple d2jsp accounts.

Means you have more then one account.
If i was you then i would just stick to the traiding forums for a while... you'll get used to the terms and get some posts under your belt.
General chat is kinda the lions den for trolls.

As mentioned, General Chat is a good place for something like introducing oneself.

In regards to the hassles you may encounter as stated by Newporg, all you have to do is report posts that break the rules.

If anyone flames you don't respond to it and use the report button.

Don't allow people who break the rules dictate where you can make appropriate rule abiding posts,(such as General Chat)

Here is a good section where you can meet people with similar interests that you may have:

http://forums.d2jsp.org/forum.php?f=185

The trading grounds are for trading only and you should not introduce yourself there as it would be spam.

Good luck!