I'm currently watching My Sassy Princess and I love the ML because he is bold. He doesn't hesitate to visit the FL at night despite the fact that she is a princess. The same goes in Love Scenery, the ML doesn't hesitate to chase the FL although she is a famous singer and he just a student.
Do you have some other recommandations with a bold male lead?

Secret Love Affair 
Something in the Rain 
Whats wrong with secretary Kim 
Scarlet Heart Ryo - the main couple he is quite bold
One Spring Night

Cdrama;
Sweet Teeth - 3 couples, all three have somewhat bold characters

A Business Proposal Both MLs are pretty bold.

Tie Me (K)not This is the boldEST thai character I've seen. One of the best thai drama ever, unfortunately the subbing is very slow.

My Fated Boy 

Before We Get Married he's almost bullish with his boldness

The Beauty Inside He's bold in a 'I don't care what happens anyway, I might as well request what I want' kind of way

It's Okay, That's Love 

Cheese in the Trap 

Discovery of Romance 

  • Love Alarm
  • Pachinko
  • My Name
  • The King: Eternal Monarch
  • Twenty-Five Twenty-One
  • Weightlifting Fairy Kim Bok Joo

I'm currently watching Search: WWW. The ML is the definition of bold and self assured in my opinion. 

i dont know if it would fit exactly but the k2 and vagabond does fall somehow in that category

the hier 

boys over flower