$wpdb->prepare is not working like mysql_real_escape_string

I’m working on a WordPress plugin and recently I have planned to migrate from SQL to $wpdb. I’m using a method called $wpdb->prepare instead of mysql_real_escape_string but it does not work. Here is what I tried:

Code:

echo $fetch_row;

Output:

a:5:{s:9:”task_name”;s:10:”Backup Now”;s:9:”mechanism”;s:10:”singleCall”

Code:

echo mysql_real_escape_string( $fetch_row )

Output:

‘a:5:{s:9:\”task_name\”;s:10:\”Backup Now\”;s:9:\”mechanism\”

After mysql_real_escape_string function executed you can see the difference in the string.

I came along this question on stackexchange so I used $wpdb->prepare($fetch_row) but the output did not change, it is just like the input.

Suggest me where I’m doing mistakes.