。
Tomorrow is a brand new day.
Literal
Tomorrow [topic-は] again new day [subject-が] come-arrive.
新たな日がやってくる — 'a new day comes along.' やってくる is a compound verb (やる + 来る) meaning 'to come along, to arrive' — more vivid than simply 来る. また ('again') implies cyclical renewal. An uplifting, almost poetic statement.