This is going to take time/ This may be difficult/ We will be busy finishing this task

I haven't heard this idiom yet either, but here's a link to the meaning: http://idioms.thefreedictionary.com/have+work+cut+out

If you have your work cut out, you have something very difficult to do. It is an idiom. Another way to say it: We really have a lot of work to do. Or you can say: We really have a lot to do. Those just a few examples how you can say it differently.