As someone who's had two self-proclaimed """introvert""" gfs:>would she be able to understand or sympathize with the effects that being lonely for so long have had on me
No. There is no truly lonely girl. Women simply can't experience loneliness on the same degree as some of us can. Even the ugliest woman has someone talking to them.>Would she be able to love me and reassure me in spite of the insecurities and complexes I've developed?
No. You having insecurities and complexes is "toxic" according to them. And from personal experience, the moment you allow yourself to be anything but a self-collected doer, she'll lose respect for you.>Would she love and accept my intense introversion and mild agoraphobia?
Maybe if you're Chad.>How could I find a gf who understands being lonely when it seems like every girl is surrounded with attention and validation?
You're going to have to settle for the ugliest of girls out there, and even then they wouldn't really understand.