思っていた以上に嬉しいって英語でなんて言うの？

"I knew I would be happy, but I didn't expect to be this happy" is a way of explaining that your feelings of happiness were greater than you first thought that they would be. "I felt happier than I could have imagined" suggests that you were happier than anticipated!

If you have feelings in your head then these are called your 'thoughts' so you would say 'than I thought' or 'I didn't think' this means that you didn't think it would happen like that or your thoughts were different

In the first sentence, "excited" shows a form of emotional energy. Emotional energy is what makes you feel the way you do when you see your niece. In the second sentence, you are expressing exactly the same as in the first sentence, but you are using a different expression. The third sentence has the same meaning as the first two, but it is just a different expression as to how you feel inside with your niece being born. In both sentences, you express how you feel about your niece being born, which is happy and excited. emotional - feelings expression - giving one's feelings over the moon - extremely happy jumped for joy - very happy / pleased

You wish to express your happiness that your niece was born - you feel even happier than you thought you would.

I am so happy I feel like I am walking on air. I just fell in love with my baby niece and feel ecstatic! I didn't know I could feel this happy until I saw my baby niece. This baby makes me feel so much joy and happiness! I have never felt this much happiness before.

"Happier than I thought" and "Didn't think I could be this happy" are expressions that are stating that you are happier, feel better than once thought, this is often used in very happy occasion.