Girl's Behavior

Why is she quiet all of a sudden?

My brother dated a friend of mine for a while and things didn’t work out, she broke up with him. When they were dating she was going through a rough time at work and had some personal problems at the time and she shut my brother out. My brother was hurt by the breakup but now seems to have moved on. My friend is not a loud person but she has al it to say sometimes and generally has an outgoing personality. After the break up things started going well for her in her job and things got better personally. She seems happier and she and my brother get along even though they are not together anymore. But she is not outspoken anymore, she seems reserved and quiet in general. Even my brother told me that he bumped into her and she waved at him and seemed reserved and quiet, he asked her if she was okay and she smiled at him and nodded her head without saying much. We both notice she has been quiet lately but she doesn’t seem sad or depressed or anything like that. She is even less opinionated and her fon her facebook, she posts jokes and silly stuff but she used to post deep philosophical stuff but not anymore. Why do you think she is like this?
Why is she quiet all of a sudden?
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