Humans are sexually dimorphic in the vast majority of cases.
Female is a biological descriptor of a person born with XX chromosomes and generally means that that person has female primary and secondary sexual organs.
Woman is a word which is defined as meaning an adult human female.
Feminine is descriptive of a series of behaviors, norms and mores imposed on women and girls by society, to which those women and girls are expected to conform. This is their gender role.
Gender is socially constructed. Sex is biological.
You can feel like a woman all you like, it doesn't make you one in some magical way, nor does it mean that society has to react to you as if you were one. Most people, out of good manners, will not misgender someone who wishes to present as female. However, there are no women who have penises, apart from a small number of intersex people who identify as female, but who also have some male anatomy.
Gender dysmorphia is a recognised and fairly well documented phenomenon. It would be very stupid not to 'believe' in it, and I've come across very few people who don't believe it exists.
The problem with discussing this topic is that, instead of looking at the evidence, people stand on silencing tropes and from there accuse others of erasure and other ridiculous things. You can't erase people by disagreeing with them. You might upset them, but that doesn't erase them either.