Just over 30 years ago, Francine Rivers published "Redeeming Love", a re-imagining of the biblical story of Hosea as romance fiction.

It became a bestseller and remains a fan favourite in the Christian fiction genre, selling 3 million copies to date and being translated into 30 languages.

The novel's translation to the big screen, however, has been less of a success.

"Redeeming Love" is at its heart a story about the unconditional and redemptive love of God towards mankind. The compelling message is that no matter how far gone you might be, or think you are, God's love for you doesn't change. All you have to do is turn back to Him and receive it.

It's clear that director DJ Caruso wanted to stretch beyond the boundaries of the conventional faith-based movie and achieve a quality of production that could be taken seriously in Hollywood.

The movie version also tries hard to be more than just a sugary Hallmark love story. It does not shy away from violence or skin-crawling seediness and depravity. Dark and uncomfortable themes like child abuse, prostitution and sexual exploitation permeate the story, and are treated with greater realism than typically seen in faith-based movies, which tend to give evil and wrongdoing some heavy airbrushing so as not to offend their Christian audiences.

Faith-based audiences may well be prepared to allow a degree of grittiness in the name of accuracy and realism, but steamy sex scenes like those in Redeeming Love are likely to be seen as an awkward and unnecessary intrusion in an otherwise inspiring movie. The fact that the movie could have shone without them only makes their presence all the more jarring.

In the end, Redeeming Love is too faith-based to have much secular appeal and yet too sexually overt to be comfortably embraced by purity-minded Christian audiences - the very audience it should have appealed to most.

Redeeming Love is out now on limited release in the UK.