我想他下一周三将会玩的很开心，对他来说那将是一个美好的一天用英语怎么说

Answer 1

I think that he will have a lot of fun next Wednesday, it will be a good day for him
请参考。

Answer 2

我想他下一周三将会玩的很开心，对他来说那将是一个美好的一天
------ I think that he will enjoy himself next Wednesday because it will be a fun day to him.