In my minecraft singleplayer world, I spawned near a village and took the villagers into my base to breed them, and for the first little bit they would breed, but then I moved them to a new location deeper underground in my base to attempt to breed them more efficiently, and they haven't bred since. They all have the same conditions met in this area as the other one, and I've done extensive research and each condition I found online (like on the up to date Wiki) I've ensured is met (two blocks above bed, bed being reachable, trading with villagers to ensure happiness, letting time go by to ensure I shouldn't have negative gossip, etc.), and they live on a little impromptu farm to be able to breed themselves. They have 3 composters and 2 of them are farmers (one is an armorsmith because I locked him in earlier), and 7 beds. The farmland has water to irrigate it. I know that the villagers have full inventories because they throw wheat and seeds at each-other in a never ending loop oftentimes. I even put a glass hole in the ceiling to make sure they got sunlight if that matters like it used to (though I couldn't find anything to suggest so).