the difference between to and for

some times, I don’t find a contingents between “to” and “for” as the following :

Mother Trisa dedicate her life to helping the poor.

here to is used as purpose , while we are knowing that “for” it should be used for purpose :
Mother Trisa deducate her life for helping the poor.


Her efforts were directed to / towards helping the poor.

but dedicate isn’t motion verb,isn’t it?
to, towards are often used with motion verbs

As well as grammar,there are some formulas,which we should know and respect,in the structure of the sentences specially for verbs.
For this reason,“to” is correct.However,“for” seems to be right.

In spite of the rules of grammar, English, like most languages, is full of conflictions. Unfortunately you just have to accept them. I am not a teacher, and I cannot argue that it is correct 100%, I just KNOW it is.

ps. By conflicts I mean right/wrong.Some meanings just overlap. What appears correct in one situation is not correct in all situations. This is one of those situations.