Unfortunately, you got a carriage ride to a Christian Church because, a mermaid what you've ridden is a Christian mermaid who wanted to be Christian like a true Christian who believes in Jesus Christ and God. If you're not sure; she must've tried to obtain conversion from her current religion to Christianity.
However; this mermaid do give people rides, but she often trick people to go to church instead, all without asking questions!
Despite her faith; the usually finds a Christian church each sunday, and she is actually a true Christian, and a true follower of Christ.
Although; that doesn't effect other Christians who ride her.
Although; she is a dictator of her nation located next to these islands what you passed earlier.