No, I don't think so. I tried to convince myself I was cisgender and straight my entire life. No matter how much I wanted it to be true, it never was.
No you can't . I did spend a bunch of time convincing myself that I was straight . It didn't work at all . I think the same goes for being gay . Haha
I think you can convince yourself but that wont make it true. For example a gay person may convince themselves they are straight. Alot of posts on this forum are straight men who have convinced themselves that they are gay even though they also mention that they do not get turned on by men and they dont want sex with men. So yes you can convince yourself.