How do I optimize a query that has high cost from Clustered Index Insert [CWT_PrimaryKey] and stop it from doing a full Table Scan?

ALTER PROCEDURE dbo.RISP_UPDATE_COMPANY_FROM_PSOFT
AS
BEGIN
  SET NOCOUNT ON;
 
  UPDATE comp
  SET
    Phone             = CAST(v.PHONE AS NVARCHAR(14)),
    Fax               = CAST(v.Fax AS NVARCHAR(14)),
    BillingAddress1   = CAST(v.ADDRESS1 AS NVARCHAR(50)),
    BillingAddress2   = CAST(v.ADDRESS2 AS NVARCHAR(50)),
    BillingAddress3   = CAST(v.ADDRESS3 AS NVARCHAR(50)),
    BillingCity       = CAST(v.CITY AS NVARCHAR(50)),
    BillingStateID    = s.StateID,
    BillingPostalCode = CAST(v.POSTAL AS NVARCHAR(10)),
    BillingCountryID  = c.CountryID
  FROM dbo.Company AS comp
  INNER JOIN dbo.Customers AS cust 
    ON comp.CompanyID = cust.CompanyID
  INNER JOIN dbo.PS_RI_TRX_CUST_VW AS v 
    ON v.CUST_ID = cust.psHomeOfficeID
    AND v.ADDRESS_SEQ_NUM = cust.psHomeLocationID
  INNER JOIN dbo.States AS s 
    ON RTRIM(v.[STATE]) = RTRIM(s.Abbreviation)
  INNER JOIN dbo.Countries AS c 
    ON RTRIM(v.COUNTRY) = RTRIM(c.Abbreviation)
  WHERE cust.CompanyID IS NOT NULL; 
    -- WHERE clause is redundant, but maybe matches a filtered index?
END
GO