Women are interested in many more aspects of men than penis size, so being well endowed is only one small part of confidence with women. So no, we don't feel like we can get any girl, or at least I never did. As far as pleasing a woman sexually, I feel that I do that, but that's a combination of my sexual style, my sexual confidence, and my size.
I don't want to get involved too much in SPH, but it's a real high when you're with a woman who's got a bit of experience, and she gasps about your size and how much she wants to get 'it' inside of her. If that happens a few times, it does raise your sexual confidence a notch, but you have to follow up your size with other things like being a considerate lover, and lasting long enough to make it worthwhile for her.
My size is both length and girth, and I think that length makes it good for long, slow languid sex. All the way in and all the way out, easy and relaxed, last all day type sex. I love that type of sex more than anything else, and it's great in a marriage to just hug and kiss and move to intercourse when she's ready and do it slowly and deeply and with lots of love. But that's what I like, and I would like to hear some of your stories about what you have done, what you like, and how well sex has gone for you.
Girth is what turns women on, and this also makes sex a bit of a challenge. Women become tighter, so if you last too long you get sore, both of you! Anal sex probably isn't going to happen, so ask nicely and don't feel upset when she says no. Anal sex has happened a couple of times for me, but a long time ago. Penetration requires lots of arousal, or else it will hurt her, so spend plenty of time to get her ready. A bit of lube is a good idea, just a bit for initial entry.
I have been married for many years and I have known lots of good women as well. Women love men when we fit well together as a couple. Fitting together includes shared values, lots of shared interests (my wife and I both like dining out, travel and reading a good book when we're home), compatable personalities and good sex. I have a happy marriage and I have all those ingredients, including good sex.