Why am I so attached to this one person online that I feel like I could tell them anything and they would still accept me but even my best friend I know in person I keep secrets from.?

I  know exactly what your feeling brother. I had gone through the same thing as well. So there was this girl I became friends with online and after some time we had become pretty close to the point where we had started telling each other some deep stuff but sadly in the end it didn't really mean anything because well we just didn't really "connect" it was more so we had fooled ourselves into thinking we could trust somebody we never met. Sorry to sound so blunt but that was just my experience with this kinda of situation. Honestly tho do what you want, if you feel that this person is close enough to you that you could tell them anything well then dang spill the beans to them. Basically just do what you whatever you feel is best ya know like just follow your gut feeling. That's all I gotta say about that :)

Explanation:

c. flammable gases, patient lying in standing water, combustible liquids near the victim