The dentist's is very busy, so we have to book the visit beforehand. You have to have your decayed tooth pulled out, but we have to wait for about one month? Can you wait? If you feel painful from time to time, let's go to the dentist's and if a doctor can spare time for you, it's ok. If not, we can visit another dentist's or we can book the date when we will visit the dentist's. Prepare to go out to the dentist's tomorrow evening. OK?

(Would you check the English expressions and correct errors, please. Thank you.)

The dentist's office is very busy, so we must schedule an appointment in advance. You need to have your decayed tooth extracted, but we may have to wait for approximately one month. Can you wait? If you experience occasional pain, we can go to the dentist and see if a doctor can accommodate you. If not, we can either visit another dentist or schedule a future appointment. Let's plan to visit the dentist tomorrow evening. Is that okay?

Here are some corrections:

- "The dentist's" should be "The dentist's office" or "The dentist's clinic" to denote the place where the dentist works.
- "Have to have" can be simplified to "need to have."
- "Pulled out" can be changed to "extracted," which is a more precise term used in dentistry.
- "Dentist's" should be changed to "dentist's office" to clarify the location.
- "If a doctor can spare time for you" can be rephrased as "If a doctor is available to see you" to convey the idea that the dentist has an opening in their schedule.
- "Dentist's" should be changed to "dentist" when referring to a different dental professional.
- "Book the date when we will visit the dentist's" can be simplified to "schedule a future appointment."
- "Prepare to go out to the dentist's tomorrow evening" can be changed to "Let's plan to visit the dentist tomorrow evening."

Overall, the message becomes clearer with these adjustments.