System Administrator for handing email services

We have a real estate portal. 1. All the users signing up are required to verify their email id. The system generates an email for the user with a link to verify their email id. 2. There is a module where real estate listings are being done. We have a system at place where automatically email is generated and mailed to users of that city. Somtimes a summary email is sent next morning. The problem : 1. Verification emails are landing in SPAM folder. Also there are lot of spammers who try to signup giving a fake email id. Mails to spammers finally bounce, creating a bad repo of the domain. We need a proper system where the verification email should land in the INBOX only. 2. The bulk emails are also landing in SPAM folder. We need a system where all such emails should always land in INBOX. The required solution : We need a fullproof system where our emails should not end up in SPAM folder in any case. Do we need our own email server ? if yes then what configuration ? or should we continue using third party services ? How to make it sure that emails land in INBOX ? We are looking for a very experienced system admin only. Kindly answer our queries in your bid.