The success or failure of making any important change in your life is affected by the confidence you have in your ability to make the change
You won't get thinner, for example, if you don't see any possibility of it happening. If it seems beyond your reach, then what's the point of even thinking about it?
So, ask yourself: how confident am I that I can lose weight successfully? If you're very low in confidence, what might you do to gain confidence?
One thing you can do is think back over your last attempt to lose weight. See what obstacles popped up? What did you do about them? What could you do to deal better with these obstacles now?
Then concentrate on one goal in your life that you've reached. How did you do it? What personal skills or strengths did you use to get there? How did you overcome obstacles along the way?
The skills you used to reach that goal might very well be transferable. If so, borrow them. Bring them over and use them to lose weight. Build your confidence in your ability to lose weight on the strength of the confidence you have achieved in this other area of your life. No crime in that. All of us borrow.