How can I confirm that I'm using ecryptfs?

If ecryptfs is being used, your home folder will be mounted. You can check if it is with this command:

df -T

When I run it, I get this result:

kalle@Kalle-PC:~$ df -T
Filesystem           Type      1K-blocks       Used Available Use% Mounted on
/dev/sdc1            ext4      115376648    9002220 100513568   9% /
udev                 devtmpfs    2050188          4   2050184   1% /dev
tmpfs                tmpfs        824108       1128    822980   1% /run
none                 tmpfs          5120          0      5120   0% /run/lock
none                 tmpfs       2060264        900   2059364   1% /run/shm
/dev/sdb1            fuseblk  1953512444 1183183452 770328992  61% /media/x
/dev/sda2            ext4      861466440  138769200 678937216  17% /home
/home/kalle/.Private ecryptfs  861466440  138769200 678937216  17% /home/kalle

I have several drives on my system, but the last line is the relevant one. It shows that /home/kalle/.Private of type ecryptfs is mounted to /home/kalle, which is my home directory.

Run df -T on your system and check the results.