You're free to believe whatever you want. In every other sense, I think your deductions for his suspicion are rather reasonable, and I would agree, however...

[He looks at her like a Stern Parent.]

Somethings like "love" and "romance" are very powerful, unpredictable things. [Then his expression changes into something more calm and momfriend-like before giving her a light pat on the head.] I hope that's something you can understand.