How many volumes of the manga series of missions of love are there?

Thirty-seven issues :

Chapter titles:

1.

I Order You to Fall in Love with Me!

2.

I Order You to Hold Me in Your Arms!

3.

I Order You to Kiss Me!

4.

I Order You to Teach Me About True Love!

End of Volume 1.

5.

I Order You to Act Like My Boyfriend!

6.

I Order You to Call Me By My First Name!

7.

I Order You to Do Whatever You Want!

8.

I Order You to Confess Your Love to Me!

End of Volume 2.

9.

I Order You to Fight Over Me!

10.

I Order You to Take Me on a Date!

11.

I Want to Be With You Always

12.

I Order You to Carry Me!

End of Volume 3.

13.

I Order You to Bite Me on the Neck!

14.

Bad Boys Need to be Punished!

15.

I Order You to Stay with Me, Just for a Minute

16.

No Talking, Okay?

End of Volume 4.

17.

I Order You to Read a Secret Note, 'Kay?

18.

I Order You to Test My Instincts!!

19.

What Am I to Shigure?

20.

I Order You to Resist My Temptations!

End of Volume 5.

21.

Don't Worry, I'll Protect You

22.

I Order You to Nurse Me Back to Health!

23.

I Order You to Kiss Me Against My Will!

24.

I Order You to Tell Me How to Make a Bond!

End of Volume 6.

25.

The Promise

26.

I Order You to Be My Love Rival!

27.

Shigure's Decision

28.

Yukina's Reward

End of Volume 7.

29.

I Order You to Give Me a Reverse Mission!

30.

Suppressed Emotions

31.

First Love

32.

Shigure's Mark

32. 5

The Demon's Reflection

End of Volume 8.

33.

Unstoppable Feelings

34.

Please Look at Me

35.

Sensei's Secret

36.

I Order You to Make Me Forget!

End of Volume 9.