I was wondering if you could let me know that which one of the three choices in the following self-made scenario doesn't sound natural and why:
- Last night I went to her home. She was so sad. I immediately found out that something has happened. I asked her what's wrong with you? She said I broke up with Dany (her boyfriend). She was crying all that time. I spoke to her and after a long conversation when I was telling her my own love story, she calmed down and fell asleep on the sofa. When I .............. that everything was OK, I left there.
a) assured
b) made sure
c) got sure
For me, they all sound OK grammatically but I have no idea if they do semantically to you as natives.