We use the pattern verb+ to infinitive with various common verbs:
I have arranged to meet some friends tonight.
She has hoping to get a better job.
The negative form is not+to infinitive.
We decided not to buy the cheapest one.
We use the pattern verb+object+to infinitive with some common verbs.
I do not want her to come with me.
We use the to infinitive after various verbs connected with saying that we will or will not do something :agree, refuse, offer, promise
She refused to go to bed.
We use the to infinitive after various verbs connected with wanting or planning to do something : hope, intend, plan, want.
Here , someone is talking to a waiter:
I have forgotten to bring my money.
We use the to infinitive after various verbs connected with doing something in order to produce a certain result: try, manage, arrange, fail.
He tried not to drop the plates.
We use want+ object+to infinitive to give an order or request. Here , a teacher is giving instruction to a class:
I want you to write a story called The long journey.