Which one is more suitable for portrait shooting, Sigma 30mmF2.8 or Sigma 19mmF2.8?

30 2.8 is equivalent to 60mm, and 19 2.8 is equivalent to 38mm. Both lenses can be used to take portraits, but their functions and effects are different.

30 2.8: More specialized in taking portraits.

19 2.8: Better for shooting environmental portraits, humanities, daily life and travel.

The 14mm prime lens you are asking about is a wide-angle lens, which is better for shooting landscapes, portraits and humanities. But be aware that the edges are prone to distortion when taking portraits.

So to sum up, the better one for daily life, scenery and portraits is 19 2.8. Followed by 14 2.5. You can also choose according to the focus of shooting (19 is more portrait-oriented, 14 is more landscape-oriented) for reference.