How can a heart be so cruel?

How can a heart be so cruel?
How one can be fine after ruining all?

I have been hearing about it a lot
I am a selfish girl most likely making plot
When I am not

I thought I'm only one alone
But I was wrong

I am in a line
I have not been making plot alone
If I were making 

How can I blame myself only
When they stab you being friendly ?

Which heart would understand I am not
I were telling the truth and not after making plot