しかしながら

The word しかしながら is a conjunction that can be used at the beginning of sentences to mean "however" or "but." It's a highly formal expression and is generally used in written language.

この論文はすばらしいと思う。しかしながら、賛成できない点もいくつかある。
I think this essay is wonderful. However, there are also some points that I can't agree with.

リーさんは頭がいいと思う。しかしながら、薄情な人そうだな。
I think Lee-san is smart. But I hear that he's a cold-hearted person.

戦争がよくないことは、みんな分かっているはずだ。しかしながら、未だに戦争は続いている。
People should know that war is bad. Nevertheless, war still continues.

分かってるよ。しかしながら、十二午前のあと医師が病院に入ってはいけないになってる。
I understand. However, the rule is that doctors must not enter the hospital after 12 AM.