Convinced vs Choices:
I may or may not be convinced when I choose to do and believe something. On a conscious level, that is true, psychologically.
On a subliminal level, that is even more true. Being convinced can be emotional, intellectual, physical, metaphysical, theoretical, abstract, and/or spiritual. There are different dimensions, different levels, to all of this. We feel things. We do things. We say things.
You can be right to the extent of absolute objectivity, perhaps from a perspective of omniscience. The problem is that we may not always have a clear understanding of what is really happening.
We can be too blinded by subjectivity, etc. So, being convinced can lead to me believing certain things.
However, I can choose to defy that at the same time. I can harden my heart and choose to go against what I am convinced of. People do this all the time. People do what they do not believe in all the time.
Freewill vs Determinism
So, life has freewill. If what you are saying endorses predestination and no freewill, then you are in fact promoting human-robotism or some kind of intellectualism to say that once you convince somebody of something, then they will do what commanded them to do perhaps.