How do i get my ringnecks to court with one another?

I have a indian ring-neck who is 11 years old, he was my brothers bird first but he recently moved away so now i have him, When my brother moved away Rastus started regurgitating his food and i was told he needed a mate so i bought a bigger cage and got him a two year old female she lost her partner last year. She is showing signs that she is interested in him but he has never been around another bird in his life and he growling and hissing at her when she is near, Rastus is still regurgitating his food and Bella comes up when he has walked away and eats it. How long will it take before Rastus starts to like her? Ive been looking online for someone with the same kind of story but not much luck please help