I am making on telephony app. I am using Twilio sip trunk service for calling with US number. So my call will be routed from US to India. So my question is will this routing add some latency in calling experience? and also sometime it stuck at start and don't folllow instruction so what can be a problem? My network connection or anything else. How can I stabilise livekit?

There maybe minimal latency for that use case. But India has pretty strict rules about Telephony calls in India so I would urge you to check their rules and legislation to make sure you meet their requirements.