Does my supervisor want me to do my Ph.D. with him or elsewhere? I am currently doing my master's under the supervision of an assistant professor. He's brilliant, professional and an amazing mentor. He is supportive but at the same time knows when and how to be tough on me enough to challenge me intellectually and push me to get out of my comfort zone. For all these reasons, he would be the perfect supervisor for my Ph.D. The only problem is that he doesn't work on the same topic as me (and doesn't really have much experience with it either) and seeing that it's a new and tricky topic, I need someone experienced in this particular area.

I spoke to him several times about my plans for my Ph.D. and mentioned that I planned on applying to several major universities and that I was looking for supervisors working on my field of interest. He would keep bringing up the Ph.D. programme at his departement and would tell me that I could work with him and also someone else from another university (co-supervision). I said it could be a good idea, but of course, I was still considering the Ph.D. programmes at other universities (which, I think is normal, I'm only keeping my options open). Of course, he knew that I could enroll in better programmes elsewhere, but he still asked me to stay, more than once (which is flattering since I respect and admire him). The Phd programme he's suggesting is the best option for me ONLY in terms of funding, because it has a special offer for foreign students paying extra fees (which he also knows...).

Now, I recently had a meeting with him and I mentioned that I wanted to do an internship in one of the universities I'm interested in. He said "It's a good idea and if you like the experience, you can decide to stay there for a Ph.D.". That was one hell of a slap in my face... He basically told me "Hey, I changed my mind, you're not a worthwhile student, finish your master's, then you're out". So at the end of our meeting, I decided to be honest and asked "okay, so if I understand correctly, you no longer want me to stay here for my Ph.D.?", to which he answered "No, I do. But I want you to explore your options. I don't want you to stay just because you think it's your only option but because you believe it's the RIGHT option for you."

So now I'm confused. Does he want me to stay or does he want to get rid of me?
As Peter said in his comment, ask him.

However, having said that, and based on what you have said, it is very clear that he is not 'kicking you out' at all - on the contrary, he is demonstrating a very positive and constructive approach - by telling you that you have to pursue what is best for you.

Having said that, you need to consider a key question:


What is/are your goal(s) after you complete your research?  


The professor is, as you say not an expert in the field you are interested in, and what he is suggesting is that, as this is the case then the internship may lead to opportunities that are more in line for your plans.

He is also seemingly suggesting is to pursue the internship and then decide where and what you want to study for your PhD.

Ultimately, the decision is yours to make - he is helping you to help yourself in this regards.

But, a piece of advice, do not assume to know the intentions of anyone - take his advice on face value and in the spirit that it has been given.