Not to try to sound like a smartass about this, but I think therapy might be more beneficial if you want to have more confidence. You will learn skills that you can use for the rest of your life. A spell may work a little bit here and there, but it may not be long lasting. And...most spells don't work, it's the placebo effect that makes you believe they work.
The reason I say therapy is because there is nothing more attractive than a person who fully knows themselves and is comfortable with who they are. And therapy can help you achieve this.
