Be easier said than done
Definition 1 of 1
Pro Tip 1/3Taking Action
Refers to the difficulty of actualizing an idea or plan, not just the concept being hard. 
Losing weight is easier said than done.
Pro Tip 2/3Cautious Optimism
Used to temper expectations, acknowledging that success may be harder to achieve than anticipated. 
Overcoming this crisis is easier said than done.
Pro Tip 3/3Potential Challenges
Suggests there may be unforeseen obstacles or complexities not immediately obvious. 
Starting a business can often be easier said than done.