To promise or not to promise?

When sleepy and tired, the girls would tend to have tantrums.

Then they would start creating issues.

And last night was this: MC wants to buy a classmate a very expensive gift because her other classmates also brought expensive gifts.

My answer was: let's see. Knowing that although she's tired and sleepy, she would remember.

Her papa said, there are also things that are not so expensive yet great to have, too. MC wont hear about them.

She wants to extract a promise that she buy an expensive toy for her friend.

I kept repeating,'we would see.'

She kept on crying because I wont give a definite answer. Her papa said just give in. But I told him, 'I will not give promises that would be broken.'

What happened? She was too tired to care in the end. She slept.

In the morning, I asked her what she wants to give her friend.

Her answer? 'Mama, I think I am the only one sleeping over after her party. I think my presence would already be a nice gift.'