Done This is driving me crazy

[magnetdance]

Hi, guys. Could any of you please explain the highlighted dialogue to me?
I know it's something about talking privately with your best friend but I just can't get the entire thing. HELP!

Thanks

 

[magnetdance]

Ok.. so the picture didn't work. Here's a link to it: https://ibb.co/dfXE6n

 

[OKfarm]

'talking privately with your best friend'
That's almost all and

男同士水入らず
man-to-man,without any outsiders or hindrance

This girl doesn't regard herself as the right person to
hear his circumstances.