- No one he trusts is willing to tell him he looks ridiculous.
- Multiple trusted experts and advisors have told him it looks ridiculous, but he still believes it looks good.
- He realizes it looks ridiculous, but he's unable to admit he was wrong about something.
*Some may argue there's a fourth explanation: Trump doesn't care what others think of his appearance, which is a good thing. That explanation is a non-starter; no man wears a combover because he doesn't care what others think of his appearance. The first time a man avoids his barber's eyes while mumbling, "Part it a little lower this time," he's doing it to delay having to reckon with becoming a balding man and the (largely imaginary) ridicule that might expose him to. The fact the part inevitably must continue to creep its way earward makes this something most men eventually do deal with,** because at some point the actual ridicule of the side-part overtakes the imaginary ridicule of balding. Any man whose sidepart is as low as Trump's and whose profile is as high has been hearing himself ridiculed publicly for a very long time; clearly to Trump the imaginary ridicule associated with being a balding man is still more terrifying than the actual ridicule he gets for his combover.
**By either shaving their heads, wearing hats everywhere, or just telling their barbers, "Let's stop this nonsense."