Let's settle this problem once and for all.我们把这个问题彻底解决了吧。

Winning its fourth straight championship game, the team proved once and for all that they are the best.连续四次赢得比赛冠军，球队彻底证明了自己是最好的。

I'm asking you once and for all.我最后问你一遍。

Please, once and for all, stop worrying.最后再说一遍，请别担心了。