This question is lifted from author Sahar Sabati's informative Ask an Author series, which ran from 2015-2016 and included responses and reflections from English-speaking authors from around the globe. Since I'm often asked these questions by readers, I have republished my answers here with Sahar's kind permission.
In my heart I feel I’m not a natural writer – not like some of the other writers here ‒ so my characters don’t often to speak to me. Not typically. At least, not until I know them really well and that doesn’t tend to happen until after the book is written. More often, dragging the thoughts and fears from my characters is like hauling water from the bottom of a deep well; I get there eventually, but not without a lot of hard work. But there have been times when I have had an idea for one of my characters and they have refused to play along. For example, I once wanted a heroine to cheat on her boyfriend. She refused to do it. “I’m not that kind of girl,” she insisted (yes, this time the character was riled enough to talk. Actually, she spat it at me in a rather indignant fashion). “I’m prepared go as far as contemplating it,” she said, “and I might even get myself into a slightly awkward and compromising situation that could potentially be misconstrued as cheating by observers, but don’t ask me to cheat on my boyfriend because I just can’t.” Please. It would really spice up the plot. “Too bad. You want spice? Get yourself another heroine.”