How an i tell if who i send a email to opens it? search MSG cant help cause i went back to read the sent mail

It depends on the email client you're using. If you use Microsoft Outlook for example, you can specify if you want to send a "read reciept", the end-user still has the option of saying no, but it is one way of checking. Other than that, the only 100% sure way is to ask the person directly.

The first answer given by "Applezdew" is absurd. How can you get someoneelse's password? Asker should protest this answer. Serious questions should be answered seriously.

Suppose u send a mail to ur friend and you have ur friends e mails password n go back to check if that person has read ur mail or know, you can come to know bout it by the color of da message if dat person had read da mail then it will appear darker or else it will be of da normal color. Now if u don't remember if it was dark or light n u click on da message then it will turn dark n there is no way u can know if its been read before or not. All u can do is make sure if da person reads it again, just click n da message n turn it into not read n it will turn to normal color again, but remember ur friend can also fool u by readin n turning it into not read so be careful, the only foolproof was is to ask da concerned person if he/she has read da mail or not

im not sure how to do this on a computer, but asking them always helps......