How can you trust people without knowing well for which you must chatt for longer

Hello and welcome!
How to trust? For me it is easy, I always invest my heart and the truth. Becsuse, the input determines the output. And the output is really great. I bless the scammers and then block them. That's okay. By Mingle2 God gave me the true loving caring husband. By Mingle2 God gave me the ministry "Online mom and Sons", with more than 140 online sons, from 28 countries and of any religion.
Be careful and pray to God to help you finding your love. God bless you. Mom Vera

Chatting longer doesn't really let you know that you can trust people.
At best that just gives you enough time for them to trip your distrust triggers. Allowing them enough rope to hang themselves, so to speak.

It's like you're saying "how do you know with whom you can trust your bank account to, talking to random strangers on a bus? You must chat for longer."
Just chatting longer doesn't mean you can trust them.
At best chatting longer gives you time to rationalize your idea of them and build up a false sense of security.

Personally, I'd say the people that want to, or offer to, sit online and chat shouldn't be trusted to actually want a healthy meaningful relationship.

I think I understand what you mean.

Something to consider;

Chatting online with anyone may not make you trust them, ever.
Trust is subjective.
Online, you can learn to trust someone with a series of questions and how they answer and if they answer similar querries with the same attitude.
That trust might allow the two of you to meet up in the real world.

In person, trust can be established in almost the same way, asking questions.
In person, you also have body language and situational reaction to help you trust deeper (or not).

What I find online is many people are afraid to trust others enough to meet in the real world. Not because they are untrustworthy. Its a safety mechanism that can get out of control.
These people likely have unfortunate experiences with someone they trusted readily in the past, so they're on guard.

Its important online to be trustworthy.
If you have a problem answering their questions, it sours the experience.
Write an honest, well-formed profile, have current pictures and fill out the details.
Look for matches that also have the same.
If you suggest a meet & greet and they refuse, they need more time.
When considering if you can trust them, use your gut reaction to what they have given you.

Choose wisely. The scammers are counting on you being reckless.

Chatting doesn't really reinforce trust. Hell, I've known people my whole life that I don't trust. If they tell me the sky is blue, I'm looking up at the sky, 'cause it sure as hell ain't blue. Then again, there's people I've known less than 5 minutes that I could trust with my life. I don't trust anyone with anything though. The only thing I trust and believe in any more is that people will disappoint you eventually, and that never fails.

Trust is built up over time in my opinion. I agree that you need to chat long enough to establish you want to meet each other and to trust them enough to turn up, and the further they live away from you probably the longer you need to chat, who wants to travel hundreds of miles for them not to turn up to meet you.

Welcome to Mingle2 and good luck in your search