The two dearest friends I have ever had in my life were male, and both ended up falling in love with me. I didn't realize at the time I was lesbian, I only understood that I could not reciprocate.
Must be the 'chill' factor that is so more unusual in straight women. The ability to hang, be one of the boys, etc, without the grief or baggage that is so typical of straight women. No offense to straight women.
I am only speculating, as you haven't mentioned any personality features of this woman.
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creature1001, as explained in the Merriam-Webster's dictionary:
Swiss cheese loving neurounique alien brained human hybrid.