in a way that causes pain

Without surgery, this animal will die slowly and painfully. 不做手术的话，这只动物会缓慢而痛苦地死去。

used to emphasize a quality, action, or situation that is unpleasant or not wanted

I am painfully aware that I have made mistakes. 我痛苦地意识到自己犯了错误。

It was a painfully slow journey. 那是一次慢得让人难受的旅程。