I'm sorry that you've had some of your questions closed. I know that it can be extremely frustrating, on the objective sites and here, on a site where you're sharing details about yourself, it can feel even worse. Please know that having a question closed isn't a failure and it's not personal.
It's also worth knowing that question closure isn't permanent. If you can edit your question to make it fit the site in terms of breadth or scope, we would love that and, if the community agrees that the new question is more limited, the question will be reopened.
While this site allows a lot of types of questions that other sites do not, we have to set some limits to keep the questions useful and easy to answer. One of the main rules of Stack Exchange is that if an entire book could be written on a subject, it's too broad. How to generally be a friend to someone of the other gender is one of those things. There are millions of ways.
So, how could you edit your question? Tell us more specifically about a friendship you're currently in with a woman that you think is heading towards the lady feeling romantically towards you and ask how to address it with this one woman. It's possible that the answers will apply more broadly but we need more details from you to propose a solution, otherwise, every solution might work, which isn't what Stack Exchange is for. Narrowing the question in this way will make it so that it can be reopened.
For your other question, the end question comes down to:
Do I have to assume this as my personality and keep living this way or I have to try to moderate myself? If yes, how?
You don't even have one question here. What you do in this situation is up to you. If you want to assume that you're stuck being the person you are, there's no reason to ask the question. Similarly, if you feel you have to change because that's what people expect of you, you're unlikely to change, no matter what advice we give.
Before you can change, you have to believe it's possible and want it yourself and then ask for help doing so. Show us that you want to change by asking a more specific question instead:
I tend to offend my friends because I say what I think without filtering it. How can I control what I write/say so that I don't sound rude?
I think we have a couple of questions that are similar to this already, so it may be a duplicate but if your details are different enough, it may be OK.
It seems that you're from Italy - it's possible that adding that information to your questions will help as how we interact is highly cultural. It may not... but it might be interesting to get some input from a fellow Italian or someone familiar with the culture.