I still don't understand why the villagers will not breed. I put a villager in a blockhouse (3 houses one on the other and another house near the top one on a side), gave him enough food,traded with him,and still he has not entered love mode. Then,I spawned another villager near him,and still he has not entered love mode. I even quited and reloaded world. Still he has not.
Notes: I play Minecraft 1.8.7,I looked up on the wiki,but I did not succeded and I do not use mods on 1.8.7.
Edit: I have already used the multiple doors trick,by adding 2 doors to the building.