You run an http debugger and find the endpoints of the app. Then it's just a matter of posting with the right values. The hard part is training the AI. You'd need a rather huge dataset in order to achieve general conversation.

Most dating apps have a webapp so you could just make a chrome extension.

There is no need to train the aim it's more than capable already. You just need to prompt it to write a romantic note in response to what they said to you