Fiarbă means 'to boil'. While it literally refers to the act of boiling, in this song, it's used metaphorically to describe intense emotions.
Irina Rimes sings, "Să nu mai fiarbă sângele în mine" (So my blood doesn't boil in me anymore). This vivid imagery conveys a feeling of intense anger, frustration, or passionate turmoil that the singer wishes to escape from, making it a powerful and memorable word in the context of heartbreak.
Irina Rimes sings about wanting out of a love she cannot put down. She opens by inviting the argument, telling him to scold her and say whatever comes to him, because a fight is easier to face than the thing underneath it: she has no strength left to break away from him.
The relationship runs on the wrong rhythm. They meet too often and it hurts, and they talk too rarely, which is harder still. Her blood boils when she touches him and she can feel that he would rather she did not. So she wants to shout loud enough for God to hear her, loud enough to be heard from three stops down the road, loud enough to be heard from inside her own house.
The chorus holds the contradiction the whole song lives on. He told her he loves her, and she cannot wait to stop loving him. She calls herself a cold soul with warm blood, and she says he is lying when he promises he will not forget her, because she is already waiting for the day he is the one who has been forgotten.
He told her once that it would pass, that it would burn itself out quickly. Her answer closes the song. He has no idea how cold she has become.