You take responsibility to overcome the misacts of others not to excuse the misacts of others.
a.) Girl gives you the wrong number. Yes you could have set a better impression, but she is still wrong.
b.) Girl talks leads you on with no intention of dating you. Yes you could have asked logistical questions to not be led on, but she is still wrong.
c.) Girl cheats on you. Yes you could have been a better judge of her character, but she is still wrong.

You can do more but you still got done wrong. I get the impression sometimes that some people think it does not even matter what other people do and that guys encourage this. Having dignity means ,you feel deserving of proper SPAM. If you let people treat you any kind of way you can lose your dignity.

At the end of the day, you are responsible for how you treat other people and the effect your actions have on others. You have to hold people to that.

People always say take responsibility, but you have to understand that people are not always prepared to take responsibility. You become prepared by building your confidence, building your character, and acquiring knowledge. Then you protect the strength that you have built by demanding respect. Weakness is not a sin. Its always sad to see someone looked down on for something they have no control over.

~My Two Cents~