A sweetheart wedding dress shows two rounded upper areas and a visibly divided front. Pale motifs cover the lines and appear to reach towards the fuller lower area. Narrow translucent-looking bands pass below the shoulders, leaving the neck open. The person stands on a path, with the full skirt filling the lower crop before its complete hem or back can be seen. The visible surface does not establish its whole inner construction.
Look at the upper frame without added neck jewellery first. The sweetheart shape and pale pattern already create accents. If you want a necklace, try it separately and observe its distance from the central dip. Compare the shoulder bands with relaxed arms and again when reaching forward rather than judging only their still position.
Ask how the bands actually attach on your selected model. If you like the motif flow towards the skirt, inspect it with hands at your sides so the middle remains visible. A complete standing fitting with your shoes adds the missing information about the lower boundary and helps you choose bodice and skirt together.