Okuman Chouja no Kakusareta Tenshi

Nate stole Tess's heart the first time she saw him in a tux, which is how she ended up spending a night of passion with him. Six weeks later, she tells him that their wonderful night together has blessed her with a little life, but he refuses to believe the child is his. Tess is hurt after he rejects her and begins to regret the night they spent together. However, Nate later shows up at her place, having decided to pursue her. Tess briefly considers giving in to his advances, but she can't just let him have his way this time. So instead she overcomes the pain in her own heart and lies, telling him the pregnancy test was incorrect... (Source: Renta!)