Try to carry out missions with her as much as possible, and then return to the base in a timely manner. At that time, you will receive news of Quiet's escape, which means your opportunity has come.

I already have max bond with her but I probably need to have her as the active buddy right ? If so I'll start to deploy with her thanks man

M45 is a successor to Side ops 150, and you must set Quiet to its maximum bond and trigger the Cutscene for playing in the rain before unlocking this Side ops.
 
When you complete M45,M46 will be coming.

It's my first playthrough of mgsv:tpp and I'm lost on the necessary things to unlock the missions 45 and 46 because I already unlocked mission 47 can anyone help ?

Help