Here's my advice, skip the toys:
First off, stop worrying. She can pick up on your insecurity and she will NEVER cum if she think you're feeling intimidated, nervous, or anything less than Ron Jeremy. Girls need a confident man. Get that gleam in your eye, stare her dead in the face, grab hold of her and ravage that woman. Get back to your animal instincts, trust me, she'll love it. When you're tasting her sweet, delicious, womanly juices, know that YOU are the reason her pussy is wet right now. Know that YOU are the one man she has decided to give her body to. Use these things to your confidence, and approach her with it. While still being respectful of her, treat her like she belongs to you, like her body is your prized possession. Prized, but still a possession. She wants to be possessed by you, its in her instinct.
Secondly, practice on her! Get better at what you do. Go down on her again, and again, and again, learn her body, and I promise you will make her orgasm. Get good at tongue techniques, using your hands (yes both), learn the different parts of her body that trigger different responses, which parts like to be touched in conjunction, etc.. She will not only appreciate your efforts and determination, but she will most likely return the favor! Make sure you're giving proper attention to all of her lady parts, too, not just clit. Spend a significant amount of time just licking the inside walls and gently sucking on her vagina, making "Mmmmm" noises and telling her how you can feel her body gushing and twitching on your tongue, and that her juices taste like candy, lick the insides of her thighs, pay attention to non-sexual body parts and make them sexual (like her belly button) etc, etc, etc.... Read up on the topic of oral sex, women's bodies, talk to women on forums, ask questions, inform yourself! I've done this, learned some new things, and then in bed that night I get the completely out of breath, shivering, genuinely intrigued "What the hell did you just do to me!?!?!?" response after trying out my new found techniques. I'm constantly learning new things too, not just new things to try, but new WAYS to try the things we already do and enjoy. Sometimes it's extremely simple, like using two fingers instead of just one, watch the result. My lady nearly loses it once the second one comes into play. So simple, huge difference.
Third, remember that a woman's orgasm starts hours, even days in advance. The way you conduct yourself toward her prior to (and after!) having sex with her will determine the entire outcome. For example, she's far more likely to have a great orgasm after a long romantic evening of love, as opposed to when she just gets home from a stressful day at work (however the latter could have it's own value). Think about the things you say to her, how you say "I love you", pay attention to how you touch her throughout the day, all the while ALWAYS ACTING CONFIDENT even if you aren't. Be her rock, her island, her MAN and she will respond accordingly.
Lastly, don't ever talk to her about the topic of this thread, with reason #1 being why. If you talk to her about the fact that you have difficulty making her cum, then I guarantee she never, ever will. I will be the first person to say that communication is key and being open with each other about sexual topics is extremely important, but if the name of the game here is just to give her an orgasm, I don't think she'll be very hurt if you keep a secret or two in the interest of her O face. Down the line once this isn't a problem anymore, after you just got done giving her an internal earthquake and she's busy telling you how amazing that was, tell her nonchalantly "Heh, you know, I used to think I couldn't do that, but then I learned you..."
Ahh, you know, there's part of me that kindof misses this learning phase. That first time you make her explode in orgasm is going to be the best day of your life....and hers. Man I need to have sex now.....
