i think ”悲伤“ is more formal than "伤心” “难过”,they have the similar meaning.but normally we just use "伤心“ “难过” in our oral English. for instance, we would say "我很伤心！or 我很难过！”but basically we won't say "我很悲伤！” it's a little weird.lol hope that will help you.

悲伤算书面用语,就是写出来的, 口语很少用, 伤心和难过可以在口语中使用

我个人认为伤心与难过是一个意思。而且用法也想不到什区别。悲伤可以用作名词，如果用作形容词比伤心和难过更加正式一点。

悲伤可能比难过程度更深一点，如果心情不太好，我们一般用伤心或者难过，而悲伤一般都很少用，一般用于亲人朋友的离世之类，希望能帮到你

谢谢您的回答.