Cannot implicitly convert type 'string' to 'TMPro.TextMeshProUGUI'

Hello im trying to put a string to a textmeshpro text but this error keeps showing up.
8872632--1211508--upload_2023-3-13_19-43-50.png
here’s my codes:

    [SerializeField]
    public TextMeshProUGUI resulttxt;
    [SerializeField]
    public TextMeshProUGUI explanationtxt;
    private string infp;


    void Start()
    {
        resulttxt.text = PlayerPrefs.GetString("typeA") + PlayerPrefs.GetString("typeB") + PlayerPrefs.GetString("typeC") + PlayerPrefs.GetString("typeD");
        ExplainType();
    }

    void ExplainType()
    {
        if (resulttxt = "INFP")
        {
            infp = "ate angel ganda";
            explanationtxt.text = infp;

        }
    }

UI view:
8872650--1211532--upload_2023-3-13_19-54-0.png

if (resulttxt = “INFP”)

should be

if (resulttxt.text == “INFP”)