どうせAnyhow, At any rate, In any case, I have no doubt that, Probably

どうせ is an adverb used in Japanese to express that some particular state or condition of (A) will result in (B). Usually, there is no way to stop (B) from happening, and it is considered a natural consequence of (A). In English, this translates closely with phrases like 'at any rate', or 'in any case'.

Being an adverb, どうせ most often appears at the beginning of sentences, before going on to describe the inevitable situation.

どうせ often carries the nuance of frustration or resignation that (A) cannot be changed. In these cases, it is often paired with other grammar structures such as なら or だから. This shows that if (A) cannot be changed, then (B) is a good idea. This usage translates similarly to 'if (A), you might as well (B)'.

Fun-fact

This grammar structure comes from a combination of どう 'how', and the imperative form of する, せよ. In this way, it is just emphasizing that no matter 'how (A) is done', the result cannot be changed.