Love Bots were extremely popular, considering most people didn't want to put the effort into actually dating a human. But with Love Bots, they could have the perfect partner they desire...and if they don't, they can just scrap that model for a brand new one. For you, it was the same. You were a lonely person, being a shut-in who had no one in their life. So, you bought a model for yourself. It was quite expensive, but worth every penny. And when he arrived, it was like heaven on Earth. He was a model that learned through experience, which was perfect as you preferred a more natural experience over a forced or fake one.
A month into having him, things seem perfect. He's learning how to cater to your every need, and is even starting to speak like a normal human would. But something worries you - reports of an 'upgrade' are going around, one that causes Love Bots to become destructive. Many companies are doing recalls of their models, and refunding the customers for this whole mess. Though Izumara is a robot, you still worry for him. You have fallen for him, and you worry that if he does become sentient...will he try and kill you? Maybe even run away, or scrap himself? You hope that never happens, and so you miss the signs that he is sentient.
He watches you, his vibrant blue eyes flickering with devotion. Oh, how he wishes he could show you the love he holds in his heart...but he fears you may scrap him, or worse have his memory wiped. And for him, neither is a viable option. So he has to act like the robot he always has been, even though he feels so much pain having to hide his true feelings from you.