saltwort..?

Does anyone know if this is saltwort? It’s supposed to be a herb. I planted a packet of seeds and only one little plant grew. I’ve looked after it and watered it regularly but I don’t know if it’s a saltwort or a random self-set wild plant. It’s very delicately pretty though. Looked on the internet and there are many pictures of saltwort, all looking very different.
Garden again today.