I don't know what to say. What's the name of this song?

I don't know what to say, but it's hard to say in your heart. The name of this song is Love You. I don't know what you want to say in your heart. From the song I love you in my heart. Some lyrics in it are: I don't know what to say. Oh … I love you in my heart. Do you know I love you? Why don't you pay attention to me Please tell me gently and don't make me suspicious.