I give you the questions' answer.
1.They want to find the angel princess and play in the world.
2.You can always read my story,and I think sometime later,you can kown.
3.I can tell you ,yes ,she is,because I don't kown how to arrangement she behind another go to the human world.
4.He want to protection Sakura don't receive the demons harm.And if Sakura in the human world,she just like a human,so,the demons can't found she.
I must to look up the english-chinese dictionary,and if I want to read your remark.oh,I'm very tired to do this.But I feel very happy you read my story,thank you.