I saw this interesting movie few years ago online, have lost it, want to re-visit. It has elements of fantasy and magic within the main theme. English language, story set in England, made within last 20 years (possibly more recently), independent film but well made - not mainstream Hollywood at all. Feels like a Channel 4/BFI type production. For 90% of the film there are only two actors and the interest (beyond a decent fantasy) is in how their personalities come through and a relationship develops between two opposite poles.
The bereaved woman, well dressed, articulate but nervous meets a scruffy man at a train station who appears to be a 'new age' type. They taxi in daylight to a large house which she has rented for several months. The old building is in significant grounds, empty save for the two of them and looks secluded. Save for the odd couple, everything has a sense of normality to this point like a good Stephen King novel.
A discussion begins with the man professing to be a white witch. He suggests that he can open a gateway to summon an angel who will re-connect the woman with those passed. He suggests this is a long, arduous and potentially dangerous process and once started (the door is open) it must be taken to conclusion. He warns her that some aspects of the journey will challenge her mentally and physically. She agrees despite these warnings. The man seals the house.
The tension in the film is that you never know if this guy is genuine, a con man taking advantage (he is getting paid) or something worse - a satanist maybe. Or in fact, if the woman has had a nervous breakdown and is living out a sad fantasy - the direction is clever and you are given enough plausibility to keep you attached, even when he strips off and announces that they must have sex together within drawn magic symbols on the floor.
Note: It never gets too dark in the representation on screen - it's more of a well made psychological thriller / fantasy with interesting cinematography than a midnight B horror flick although there are shock moments.
Spoiler alert: At the end of the film as tension and credulity are stretched to their limits,
the man is fatally injured and the woman collapses. The camera pans to show the angel arriving in all its glory and blinding light. Everything was in fact, true.
If we can identify the film it's well worth a watch and I would love to read the novel (assuming it is based on one).