You can tell a lot about your dogs mood by watching their tail, if it moving fast they are excited, if slow they are more apprehensive. If he came from a shelter it might take some time to build a bond, looks like you have been doing a good job and he trusts you!
Discussion
It has taken years, it’s only now around 4 years later that he REALLY starts trusting us in everything without even being to jumpy…
Looong story, and still have to watch him around other dogs, and especially the 4 kittens that he absolutely view as food!