What Will Blond Highlights Look Like On Brown Hair Meaning Will They Turn Out Blond Or Red?

Depends on whether your stylist knows what they are doing or not.
Suggest you not try to highlight your brown hair yourself, because your hair needs to be lifted several shades before it will reach the blonde stage.
A properly trained hairstylist will know what to do.
Make sure you ask around and find one that does, because not all stylists are experienced in color and highlighting applications.

It all depends on if you have red pigmentations in your hair, you can see if you have them by standing in the sunlight and your hair has shiny red images ..if you have the reddishness then you probably will have to pre bleach the strands,  it is best to have a stylist do this or someone that knows what they are doing, my friend had her aunt do hers and it turns out horrible ...after she bleached it - it would not hold any color ( the bleached strands) my friend has had to cope with the bleached areas for quite sometime know and it is finally reaching the length to cut those areas off.
GOOD LUCK

Depends on how the highlights are done.  Try having the person sit you under the dryer with the color on your hair.  Bleach always takes better than just regular color