I got back together with my ex-girlfriend yesterday. I sent him a message, but she didn't reply. Reply is also a simple sentence.

You said that in this case, you must have had contradictions before, and now it suits you. After getting back together, he is still lukewarm to you. You sent him a message, but he didn't reply. Even if you do, it's just a few simple words to prove that he is still very dissatisfied with you, and maybe he is very unhappy with what you have done in many places, so although he complies with you, he is still unwilling or hesitant.