"I do not remember his name."
Translation:Ik herinner me zijn naam niet.
Here is a rule of thumb that may help you.
In a sentence with a direct object, the object can be either definite or indefinite. In a Dutch sentence, the negative comes after a definite direct object but before an indefinite direct object.
A definite direct object is one that is preceded by het, de, deze, dit, dat or a possessive or personal pronoun.
Hij heeft het boek niet gelezen (definite object)
Hij heeft niet een boek gelezen (indefinite object)
Note: The rule of thumb I have just described is for sentences that include a direct object.
Why not: ik herinner me niet zijn naam. ? Why must "niet" come at the end?
Bob, in English "I remember" is not reflexive. But its translation into Dutch, "Ik erinnere me" is reflexive.
Because you are an English speaker, it seems "natural" to you to leave out the word "me" in the Dutch. But that is a mistake, no matter how "right" if feels to you.
How do you know which non-reflexive English verbs get translated into a Dutch reflexive verb? You just have to learn them as you go.
As a rule of thumb, if a construction is reflexive in English, it will probably also be reflexive in Dutch. But Dutch also has quite a few reflexive constructions whose English counterparts are NOT reflexive.
Another rule of thumb: Both in English and Dutch, only transitive verbs can be used in reflexive contructions. So, for example, the English verb "hurt" can be transitive -- that is, it can take an object. So you can say "I hurt my friend" or "I hurt myself".
As for "I run to him", that is not reflexive either in English or Dutch. In fact, that English sentence bears no resemblance to a typical reflexive construction (such as "I hurt myself"). I'm not sure what you were thinking on that one!