I as a German perceive him as a deceiving personality, who (maybe) wants to actually drive Greece out of the Euro.

I believe you are correct in your assessment. There is a faction of neo-communist idiots inside Syriza that wants to exit the Euro (possibly the EU) and align with China and Russia. It could very well be they were the ones that forced Tsipras's hand to have this referendum, or maybe he's part of that faction. Then again he might be honestly trying to get the best deal and he is simply balancing conflicting forces inside his party, I don't know for sure.

The reason I think you might be right is that his behaviour just doesn't add up. He has manned key positions with people who seem to be purposely abrasive, not just Varoufakis but also a woman that is the speaker of Parliament who is the biggest troll ever. The defense minister is an absolute clown far-right opportunist that makes you facepalm every time he opens his mouth. What all these people have in common is that they are simply bellow par, it's like they are the useful idiots.

His whole administration has an air of something that is temporary, like he's saying I have these useful idiots for the time being until I get what I want and then I will show you my real face. He does not seem to care that he has isolated Greece nor that he withdrew the Greek delegation from the negotiations and led the country to a default.

In order for him to avoid taking on the political cost of an agreement we are now at the precipice, universally mocked and scorned, with unpredictable consequences for our and the European economy, and he acts like it's all par of the course. For me that is not how responsible politicians or great statesmen act, so for all this to me it appears that he either is extremely deficient or he has other agendas.