Since same-sex marriage isn't legally recognized in mainland China, you need to define what "marriage" means to you:

Look into Legal Guardianship (意定监护) . Many LGBTQ couples in China use this legal tool to grant each other rights similar to a spouse (medical decisions, property). 4. Safety & Vetting

Always meet for coffee or dinner first to see if the chemistry matches the profile. 5. Community Involvement

Use your bio to state exactly what you wrote: "Looking for a serious partner for marriage." This filters out people looking for casual flings.