Wrong

If you have to state verbally that you are a nice person, or that you hate drama, or that you are not a racist, it really does sound like you are trying to convince yourself more than inform others.

This lady across from me has said some very mean, sad things to her companion, but she seems to start so many of her sentences with, "I am a very nice person, but..."

If you need to qualify the statement with, "but," then you are disqualifying the statement.

You are not a nice lady. You have a spiteful, morose candy coating, and are  filled with a sweet rage nectar. There is nothing at all nice about you. Embrace your evil.