Wooooah, what's the source on this? it looks like it's from Where gennos and sonic fight, But uhh, as far as i know, sonic is totally not a chick (No matter how much of a chick he looks like.) Pic is the original
Probably the only reason. Tatsumaki and Fubuki have extremely similar personalities. Just that due to Fubuki's massively lacking power in comparison to her older sister and obviously Saitama, she was cowed into becoming friendly much easier.
Anyone following the ONE manga can see Tatsumaki's not much different. The way she acts is just the only way she could deal with a society that hated her and her little sister.
Her first love was an arrogant jackass, he ex probably lost his ability to show any affection towards her when he became a robot, her Dad's a cool guy, and her brother is incapable of giving a **** about anything... You're in a great spot!