Toxic people know that they are ugly on the inside and know that nobody would be attracted to who they really are. They are not going to advertise their mental instabilities or their twisted emotional needs. A narcissist will not explain to you that they need to put others down because of their ‘babydick syndrome’. A sociopath will not explain to you that they need to hurt others to feel in control. Toxic people need to pretend to be somebody that they’re not to lure others into a relationship with them.
So, the question you should ask yourself is this: are you attracted to their false self or their true self?
Being in love with their false self is an illusion. That person isn’t real. Being in love with their true self is unhealthy. That person will not work towards a healthy relationship with you. They will not communicate their toxic needs to you. There’s a simple way to prove that to yourself: ask them to merely try to change and to be honest with you. If they can’t be bothered to try, then you should not expect any sort of a healthy relationship. They are not going to act in your best interests and their actions will speak louder than words. They will not change for you.