Most Helpful Girl
You get friendzoned because you're acting like a friend, and they think think you're genuinely a friend. Friendship is more important than a relationship that may last only a few months, so they're not willing to risk your "friendship".
Those women may not even know that you're interested in that way. You should be more straightforward with your intentions.
Most Helpful Guy
You are hearing their words, but not getting their message. They say things like "I don't want to ruin the friendship" but what they are telling you is "No, I'm not interested in you as a romantic partner." Your inability to understand what they are telling you is a big part of the reason they aren't interested.
So the problem isn't that you are overly nice. The problem is that you are socially clueless. A lot of communication between adults occurs between the lines, not in the actual words spoken. You need to mature socially and then you will have more success dating. Start by just making small talk with everyone. Girls you want to date. Girls you don't want to date. The guy at the supermarket. Learn their names. Ask twice if you have to. Ask three times. No problem. People will be happy you care enough to ask.