Why trust or why should I trust condoms if preventing STDs and STIs is inevitable? ?

They also prevent pregnancy unless you don't care about that

Sorry but your question doesn't make sense.

inevitable = unavoidable

Why trust or why should I trust condoms if preventing STDs and STIs is unavoidable. 

Condoms have been proven to reduce the risk of STI's. Nothing is "inevitable". 

Be selective with whom you have sex with and always use protection. 

The alternative is to act like an animal and hump anything that moves including the one tooth homeless women selling sex for $10 then you will come down with every STI out there. 

Condoms are the best form of protection from std's but if you can't trust the person you shouldn't be having sex with them.

And std's isn't inevitable I've had tons of sex and I never had any std or sti