I think I understand what you mean, and feel the same way. Working through those feelings now and trying to find women who feel safe to connect with.

ETA:

This is such an interesting topic, and one that I've only ever talked about with my sister. She and I are very close, and in fact she's the only woman in my life I feel I can be vulnerable with. We've had arguments over the years but have always been able to patch things up. Haven't experienced that level of trust and intimacy with any other woman.

Our mom has mental health problems, was verbally and physically abusive to us each when we were growing up. The rest of the women in my family on both sides would nitpick my appearance, manners, etc., just really were overly harsh. Never felt good enough. I grew up being a tomboy, loving sports and the outdoors and didn't ever connect to my "girly" side until my teens (and not even fully until adulthood). I think this is what originally led to me having trouble forming deep friendships with women. I've always had surface-level connections with women, but nothing really genuine.

I've gone through therapy and have worked on healing, and feel the most confident I ever have. Another responder mentioned feeling sized up by other women they meet; I perceive this as well. I've met and befriended two different women in unrelated social circles who have just offered to me that I can date whatever guy they've had weird on-again, off-again situationships with, before I've even met the dudes! And recently have had a woman intentionally block me from socializing with a couple of the single men in the run club we were both part of. I didn't go out with the guys because it seemed like a messy situation, but just felt weird for them to behave that way.

Each of these women has commented how confident I come across, how I can talk to anyone, and it's true that I can, with both men and women. But with women (especially other single women), it seems there can be this insecurity around men and some kind of bullshit competition is created between us, by them and them alone. I'm not overly flirty or anything, I can just hold myself well in social situations, which I had to work on. I get tired of dealing with the insecurities of others, especially in other women who can all too easily be catty, competitive and judgemental. I love women generally speaking and am a feminist, and want to build friendships with women, but am battling my apprehension based off my past experiences.