How to confirm that he has read the text message?

Whether this function information has been seen by the other party cannot be directly judged.

It can be judged by SMS prompts. When the other party receives the short message, the mobile phone will display a prompt, such as "XXX has received a new message", then you can know that the other party has received the short message. But if the other party doesn't open the text message, it is impossible to determine whether the other party has read it.

Some SMS service providers also provide message reading receipt function. When the other party receives the message and reads it, the system will automatically send a read receipt to the sender to inform that the message has been read. However, this function is not provided by all SMS service providers and needs to be determined according to the specific situation.