How can I know if the other party has seen the SMS sent by Apple's mobile phone?

Apple's mobile phone can't know whether the other party has read the text message.

According to the design of Apple's mobile phone, the direct reading confirmation function is not provided after the SMS is sent. Therefore, it is impossible to know accurately whether the other party has read the text message. Although in iMessage, the sent message will show "sent" or "read", this only means that the message has been successfully sent to the other party's device, but it does not completely mean that the other party has read the message. Therefore, the SMS sent by Apple's mobile phone can't provide confirmation whether the other party has seen it.