I'm guessing that you are frustrated that someone who you appreciate for how good they are to you, just doesn't turn you on as you need them to, in order to feel you love them. That, or you are trying to say that you have been unlucky in love, having fallen again and again for people who were NOT nice to you.

In either case, no one can DECIDE to love someone. You can only decide how you are going to comport yourself, how you will behave from one moment to the next with them. Whether love blooms within you or them or not, isn't up to either of you.

If you are finding that you fall for the "wrong kind of people," the way to work on that, is self knowledge. Figure out what it is about someone who IS bad for you, that you find so desirable. There is usually some confusion in your inner thoughts, such that you are mixing up things like decisiveness with selfishness, or strength with casual violence.