Thoughts on the scenario after completing "Hammers of Fate".

I don't understand how Isabel could fall in love with Railag – the one who killed her first love, Nicholas? Even though Railag apologized, how can you forgive someone for something like that? I think Agrail killed Nicholas simply out of jealousy because Isabel loved him. And in general, judging by her vow after Nicholas's death, she was supposed to hand him over to the inquisitors and then have him burned. But after a few explanations, she just forgave him. I don't understand how that's possible...