Can I listen to what my heart says? How do I know whether it is right or wrong?

Thanks for the question.
No matter what we think of a person, good or bad, we need to look at an important thing that the Bible tells us. It tells us that our hearts are corrupt and sinful. (Jer 17:9, Mark 7:20-23)
But once a person comes to know the Lord, He or she has a new heart - in the sense that it has a new attitude towards sin, new goals, new principles , new standards etc. This is manifested more as it is transformed by the word of God. So even while our hearts are intrinsically wrong and corrupt, God can change our hearts. (Ezekiel 11:9)

But the devil can still trick us and tempt us, if we are careless.(1 Peter 5:8) So it is essential to trust the word of God primarily and not simply what our heart says. So even when we are in confusion or when we are not sure whether we should listen to what our heart is saying, we can go back to the word of God to check and recheck what God says about the matter.

God will never put thoughts in your mind that requires you to disobey His words or go against His will. If it is not aligning with what the Bible says, you need to see where you got an idea or thought from. That's a good filter to by. Also use the filter provided in Phil 4:8 to check you actions, words and thoughts.

So my advice to you is to abide in the scriptures. We cannot become good on our own, but we need the strong influence of God's word in our life to be right. Only by abiding in his word can we be on the right track. (John 15:1-17, John 17:17)

Do take a look at the video link that's given. God bless!