I have been developing a classifier with machine learning to know if two texts are related or not. By that means, if they are talking about the same topic or not. I have tried to gather data but, so far, I have only come up with the FNC dataset (http://www.fakenewschallenge.org/) which is more a problem o stance classification but I can modify it slightly to only classify texts as relevant/irrelevant between themselves.
Where can I get datasets for sentence relatedness or stance classification? Thanks in advance.