【Casual】Useful Common Response Phrases.

うそ！！
うそでしょ（a bit feminine)
うそだろ　(a bit masculine)

Really？ Are you sure?

※commonly used among young people in Japan. It's considered a casual and informal expression, often used in everyday conversations

I know!!!I get it. I know how you feel.
This expression is used when you sympathize with the other person.

分（わ）かる！！！
分かるわ～(This わ at the end is used by any genders)

だよね！ だよね～ Right?? I know right?
 when you strongly agree with someone.
だよね？？【Pitch rises at the end】Seeking for agreement

（そう）だよね！！
（そう）だよね～
（そう）だよね？？

Is it possible? Has it really happened?
It's a casual expression often used in conversations among friends or in everyday situations to convey a sense of astonishment or curiosity.

That is nice. That's good. I'm jealous.

It's often used when someone is expressing approval or expressing a desire for something they find appealing.

よかったね！
よかったな（more masculine)

It's often used to acknowledge or confirm information that you've just learned or been told.
The meaning doesn't vary significantly with tone or facial expression.

そっかぁ。(meaning varies with your tone and facial expression, if your tone is low and sad it shows disappointment. with smile and happy tone means the opposite.