I personally think that asking this kind of question most often calls for the other person not to be honest about it, even in everyday relationships. I imagine that most Ts would never say "I don't love you" and few would express the opposite ("I do love you") as well. Most would probably talk around it and/or challenge the client to investigate why they have a need to ask it. I also believe that in this area, actions usually speak louder than words and tend to be more genuine, and it's possible between T and client, but I imagine that love between T and client is probably something that develops (if) over a longer period of time, but then it's palpable. I would definitely think that interest, caring, liking, appreciation, gratefulness etc can be more common in this context and in most professional relationships.