Trustworthy seller?

Hi,
I'm a German PhD student wanting to buy my first car; I'm unexperienced with buying cars, especially in the US. I'm interested in buying a 2009 VW Eos, mileage 140k, from a private seller (found online). I met the guy today and had a test drive. The car looks great and drives well. However, I'm unsure about a few things:
- The seller's name is not on the title. He said it's his father-in-law's car. However, the name on the title is female. He said it's his father-in-law's ex-wife, who got it after their divorce. The title transfer to this woman was just 2 months ago.
- He showed me a mechanics report, done 2 days ago, which however looks really unprofessional. It does make sense, though (it said the front tires are a safety issue, which the seller didn't mention to me, but definitely seems to be the case)
- He will try to find documentation about past repairs, however is unsure if he will be able to get it
- the price (5000, negotiated down fairly easily to 4600) seems low for a nice car like that. He said he has interested buyers, so why did he easily lower the price?
- He also suggested to put down a lower selling price on the title so that the sales tax will be lower.

I'm sorry about being distrustful, but I'm just uncertain as its my first buying experience. I would appreciate your feedback!

Thanks,
Philipp