You cannot say " I have no heart to do sth." For example, Chicken soup for soul, not for hearts. % J/ P) A, s6 e8 {, v
Your context is not very clear. So can you explain the contexts more clearly? 4 O* B$ ~5 \/ O6 {8 @Why you don't want to bother the boy again?
For the first context, just say I am sorry to bother you again. 0 S, \" U) V6 V# f9 V$ t6 u. n
For the second case, I don't think you can use hearts in this expression. You can say I am not meant to do sth...