How can you know if he loves you?

You'll just know if he does! You will just get this feeling that can't be described, and he'll either tell you when the time is right, or something will happen and you'll never forget it!
His actions speak louder than Words. If he respects you, treats you well, and takes care to protect you it is possible he loves you. Love comes and goes and it changes with time. If this is a new relationship he may love you in a different way than he will a year from now. Ask him how he feels.