What does the sentence 多用心译 mean?
A whole sentence would clarify the meaning. Do you have the sentence?

In my opinion, '多用心译' just means 'be careful when translating'. I can definitely empathize! 

People say that the German President Heinrich Lübke once said to Queen Elizabeth II, "Equals goes it loose." They were at a horse race, he wanted to say, "It will start in a moment." but his English was not good and he translated from German literally.