Search txt file for particular matching character

This method will return the string array of match words

I do need to search the text file contain list of word per line and i want to return list of matching word from that text file.

example for “trainer”, I should get a list equivalent to [“terrain”, “trainer”, “retrain”].
    
        public static string[] GetMatchesFor(string word, string pathToWordsDatabase)
        {
            string[] Database = File.ReadAllLines(pathToWordsDatabase);
            string result = string.Empty;

            foreach (string str in Database)
            {
                bool isMatch = false;
                if (str.Length == word.Length)
                {
                    char[] chrArray = word.ToCharArray();
                    foreach (char chr in chrArray)
                    {
                        if (str.Contains(chr.ToString()))
                        {
                            isMatch = true;
                        }
                        else
                        {
                            isMatch = false;
                            break;
                        }
                    }
                    if (isMatch)
                    {
                        result = result + str + ",";
                    }
                }
                else
                {
                    continue;
                }
            }
            int count = result.Split(',').Length - 1;
            string[] resultArray = new string[count];
            for (int i = 0; i < count; i++)
            {
                resultArray[i] = result.Split(',')[i];
            }
            return resultArray;
        }