我要就寝怎么说英语

To say "I'm going to sleep" in English, you can say "I'm going to bed" or "I'm heading to bed." You can also simply say "I'm going to sleep." All of these phrases mean that you are planning to go to bed and rest or sleep. Here are a few examples of how you might use these phrases in a sentence:
"It's late, so I'm going to bed."
"I'm feeling tired, so I'm going to sleep."
"I'm heading to bed, see you in the morning."