Yvette doesnt get pregnant no matter what I do. Is it a bug or is it suppose to take so much effort ?
Read the provided WT closely.. The Nun will give Yvette potions every day to make sure she isn't pregnant, until the Nun willingly accept the MC's seed.. Winning against her in a battle of Will doesn't count!
So first you have to win and then the next day have sex with the Nun without a battle, you should be able to see the difference..
After that, your seed should stick and Yvettes pregnancy progress as it should.
Furthermore in my game play, Yvettes mom had to be not pregnant before Yvette could get pregnant, but that might just have been a fluke of rng..
The last part of the WT explains what the chances are for the Women to get pregnant and what increases said chances.