I can relate to this so much! I’ve never been a very girly girl with pretty dresses and high heels and lots of makeup, but since my teenage years it happened quite often that boys would misinterpret my being nice as flirting. Even though I never wanted to, because I didn’t like these particular boys in a romantic way, I seemed to attract them all the time. Which made it really hard to just be friends with boys, so I had to learn how to brush them off and so no a lot of times, which ended in losing the friendship at all, because it was the only way to get rid of boys who thought they were getting mixed signals while I was just being myself, friendly and cute. 
But I also encountered the situation where this particular boy I liked for a long time, has been paying for my drinks when we met at cafes even though he only saw us as friends and knew about how I felt. But he was just being a gentlemen. I guess it can happen both ways, not only to girls.