1. I can easily do what you have asked.

You can just call and say “I need a babysitter tonight” and we'll send one out, no problem.

2. I am not upset by this.

“I'm sorry, but we need to go home now.” “No problem.”

3. I was happy to do it.

“I put some lettuce and tomato on the sandwich.” “Oh, thank you.” “No problem.”

Usage notes: usually said in answer to thank you

• be on the side of the angels
• be on the skids
• be on the square
• be on the threshold of
• be on the threshold of doing something
• be on the threshold of something
• be on the tip of tongue
• be on the tip of your tongue
• be on the wagon
• be on the warpath
• be on the wing
• be on the wrong end of
• be on the wrong end of something
• be on the wrong side of
• be on the wrong track
• be on thin ice
• be on to a good thing
• be onto a winner
• be on top of the world
• be on uppers
• be on your best behaviour
• be on your guard
• be on your last legs
• be on your mettle
• be on your tail