Write letters to prisoners in detention centers. Can prisoners receive letters about love or something?

Letters sent to detainees in detention centers shall be handled by the case-handling organs. With the consent of the case-handling organ, it can communicate with prisoners. Love content does not violate the law, so prisoners can receive letters.

Measures for the Implementation of the Regulations on Detention Centers in People's Republic of China (PRC) Article 34 The communication between criminals and their close relatives living in China shall be approved by the case-handling organ, and the request for a meeting shall be approved by the competent bureau or director of the public security organ or the state security organ at or above the county level.

Article 38 If a detention center fails to entrust a case-handling organ to examine the letters sent and received by criminals, it shall hand them over to the case-handling organ for handling.