I don't see that trusting someone can be a foolishness. It's true, that China betrayed India's trust, but what if that had not happened. Then Nehru would have been a hero. Isn't it? Pakistan has betrayed India many times. Most recent was of Kargil war I suppose. Indian PM was hugging Pakistan's PM in Pakistan, and Pakistan's army were captuing posts after posts in Kargil region.
China has been quite aggressive in all of its territorial disputes, and they have used force on more than a dozen occasions in the past 50 years or so. India is not the only victim of the Chinese aggression. Check these incidents:
1. Johnson South Reef Skirmish, 1988 (with Vietnam)
2. Battle of the Paracel Islands, 1974 (with Vietnam)
3. Scarborough Shoal standoff, 2012 (with Philippines)
4. Sino-Soviet border conflict, 1969 (with USSR)
The Chinese, without any provocation invaded the disputed territories in all four incidents. They were successful in #1, #2, and #3, but got their asses kicked by the Soviets during #4.