Sometimes our reasons for seeking God are not the best, sometimes we seek God for "fire insurance" rather than because we want him. Which is ok, The fear of the Lord is the beginning of wisdom. As time goes on he begins revealing our hearts and we begin to purify our desires. We do not have to have a perfect heart to be saved, but as time goes on he will improve it.
Is it ok to seek him because we're afraid of hell?
Mat 5:29And if thy right eye offend thee, pluck it out, and castitfrom thee: for it is profitable for thee that one of thy members should perish, and notthatthy whole body should be cast into hell.
Yes it is, but as we grow in the Lord it will no longer be our main reason for seeking him.