Eventually, Mindy began to behave properly but hard feelings remained.

最后，明迪开始好好表现，但仍然感到很难过。

youdao

When will these kids learn to behave properly?

这些孩子何时才能学会规矩些？

《牛津词典》

He's a spoiled brat and it's about time he learned to behave properly.

他是个被宠坏的顽劣孩子，该是他学着行为得当的时候了。

《柯林斯英汉双解大词典》

Yes, you tell people that if they behave properly they get some sort of reward.

BBC

It will lend lots of money to big Russian companies, on condition that they behave properly.

ECONOMIST: Soft money

So smart sanctions should be able to motivate certain parties to behave properly, and I'm confident that our teams that will be engaged in consultations will continue discussing this issue.

WHITEHOUSE: Signing of New START Nuclear Arms Treaty with Russia