Every time I read the story of Jonah, I think about how a person could be upset over people repenting. Jonah's call was to go to the people of Nineveh to share about God's impending wrath. He was concerned about their response, which is why he didn't want to go. In the end, they turned to God and received an outpouring of His mercy. It's ironic to me that Jonah didn't want the Ninevites to receive God's mercy. After all, he was certainly a recipient. But it was concern about their expected response that kept Jonah from doing what God asked him to do. Could the same be true of us? There are times when I don't fulfill what I know God wants me to do because I am afraid of the response of the people. Unlike Jonah, I'm afraid people will respond in a negative way and won't listen to what I have to say. My point here is this: we can't be afraid of how people might respond to us when we're fulfilling what God has asked us to do. Our concern lies only in following through. God is responsible for the rest.
If you know that God is calling you to do something or to speak to someone, then do it. Don't worry about what the result will be because He will take care of that, and He has the ability to change hearts. Be bold, and obey the call!