If she's a believer and...
you either took her virginity or already asked her father for her hand in marriage and agreed to marry her, I think you have an obligation. If you haven't asked her father for her hand, why would you lead a girl on for 7 years, taking up 7 years of marriage-partner finding time, only to dump her during your engagement? Talk about leading a girl on. Did you discover your feelings late?
Is there any reason for the hesitation? A serious question to ask is whether she would be a good wife. If she berates you, yells at you, gets upset about small stuff and won't 'forgive' imagined offenses, is lazy, and hates children and old people, and has slept with other guys, maybe you've got some reasons. But if she's good wife material, that's a whole different story.
As far as feelings go, if you were going into an arranged marriage sight unseen, I wouldn't expect you to have feelings. If you just don't have that fresh new love excitement that teens get when they are dating, but care deeply for her, and have had strong feelings in the past, I wouldn't think not feeling those infatuation feelings right now would be a good reason to dump her after dating her for 7 years.