If something seems too good to be true, it usually is

"Trust your instincts" said Sebastian. At this point he and Matilda had been on three dates, most recently dinner at a trendy brasserie followed by an evening at the Russian ballet gala.
On the walk to the theatre after dinner, Sebastian had unwittingly pulled Matilda into the path of an oncoming vehicle as they crossed the road. On seeing the vehicle, Sebastian violently pulled Matilda's arm back towards the pavement, continuing to pull for far longer than was necessary. As a sentient being Matilda was more than capable of removing herself from danger and felt perturbed at the force he had used.
They rushed on towards the theatre. Time was running out, there were only 5 minutes left until the show started; Sebastian still had to pick up the tickets. He sprinted off into the darkness, leaving Matilda to walk the shadowy side-streets of Covent Garden alone.
They reconvened at the theatre, just in time for the start. Sitting in the dress circle, Matilda turned around at intervals to gauge Sebastian's response to the performance, he had never been to the ballet before. Each time she turned, she found that his gaze was already fixed upon her. She felt uncomfortable. The interval came and Sebastian wanted to pick up a program, he asked Matilda if she'd like anything. She said no. He got up and instructed her, "don't go anywhere".
Matilda felt isolated in a theatre filled with hundreds of people.
There was something about Sebastian that made her uneasy, she had tried to ignore it on previous dates but now a red light was flashing brightly.
Nevertheless, Matilda enjoyed the performance as best she could, despite the company. The show ended and they walked on to the tube station. Matilda's stop couldn't come quickly enough, she told Sebastian that she was going to India for a few weeks and they made no arrangements to meet again.
Three weeks later, Matilda returned to the UK and was surprised to receive a phone call from Sebastian. He wanted to see her again. Matilda was reticent. He pressed her to come up with another idea for a date, since he had enjoyed the ballet so much. Matilda responded that she couldn't think of anything off the top of her head. He asked her to come up with something and let him know.
Matilda was busy juggling multiple deadlines and could not conceive an exciting plan for a date instead she suggested a walk in the park with a coffee, in order to get to know him better. He declined, this suggestion simply wasn't exciting enough. Matilda realised that Sebastian had no intention of getting to know her with a view to a long-term relationship, he was a serial dater looking for a quick fix.
There was something disconcerting about Sebastian, whenever they had been out he would attract the attention of passers by by speaking extra-loudly and making unsavoury comments. It was as if he had some personal sense of majesty, which was clearly one of many symptoms of a mental disorder worthy of classification in the DSM-IV manual. But worst of all was his stare; cold and calculating like a predator that's just caught sight of it's prey.
Matilda was the one that got away.