The speech is a big issue if you hate public speaking. Even though you know everyone wishes the best for you, you can still dry up and look a total tool. I fully understand.
Don’t do what I did the first time and go in unprepared, thinking I would wing it on the day. That’s a disaster. There is nothing wrong with preparing a speech beforehand and reading it off a bit of paper. So long as you can read you’ll be fine ?
As for the speech itself there’s a load of stuff you can put down. First and foremost say that you feel the luckiest man on earth and you intend to devote the rest of you life to making you new wife as happy as you can. Thank everyone. Say how chuffed you are at having the great parents you have, great brothers / sisters and great friends, and how you are looking forward to being closer to your new in-laws. People love all that sort of stuff at a wedding and it’s even better if you can mean it.
You don’t need to be funny in your speech, that’s usually the best man’s job. It also doesn’t have to be very long. Mine (second time around) was a heartfelt page of A4, which went down very well. That’s enough. Keep it short and meaningful.