I teach high school right now. I ask students in each class what their math experiences have been; I give them space to vent, and make it okay to say, "I hate math." In every class I've had, there's also been someone who says, "I love math." We then talk about what has worked for people and what hasn't. I explain much of what I wrote in the comment above; many students have been blaming themselves for years of failure, and have never realized that weren't offered a way back into math. On the other hand, some students have blamed everyone but themselves and they need to start taking responsibility for themselves, and we have that honest conversation.

Everyone needs motivation to learn anything meaningful. Motivation for students can come from a desire to earn credit and graduate, a desire to be able to do a certain job, or a desire to catch up on things they haven't understood for a long time.

I connect each student's math learning plan with their job and career goals. Most of my students are at an age where that can work, if they can see the connection. This isn't just a utilitarian approach; we also talk on a regular basis about the wonders of math, and how there are efficient strategies but there are no math "tricks". I break their work into the smallest possible chunks they can earn credit for, so they get to see academic success as soon as possible.

I'm happy to share more specific thoughts here or through email, if you have a particular situation you're trying to sort out.