谁能帮忙翻译”既不回头，何必不忘．若是无缘，何须誓言．今日种种，似水无痕．明夕何夕，君已陌路．”

Since we wouldn't come back, why don't we forget about it?
If we are fated not getting together, what's the meaning of promises?
Today, nothing can cause a big splash in our hearts, just like streaming water;
Tomorrow, we will be strangers to each other if we encounter on a path.

As you won't come back , why don't you forget?
As we are fated to leave each other , why do you promise?
Things between us till the moment flows soomthly
like stream.
The future is when we go on different roads.