You can decorate a painting with glitter – doesn’t make it good.
You can cover up flaws in the foundation of a house with tape – doesn’t make the house sturdy.
Similarly, a person can charm you with their looks and shiny words, but the real personality is only revealed after you have let your guard down. Many criminals are so confident and so cool that the people close to them can’t imagine that they’d do something horrendous. This is why people are so shocked when they discover their spouse cheating. A good surface cannot hide the real truth for long.
It’s cliche for a reason: inner beauty is more important than outer beauty. Personality is more important than looks.