I am applying to graduate school currently, and all schools I've been looking at require a number of recommendation letters. I go to a fairly small school, so I've had many repeat professors. Thus, my pool of professors to ask for letters who taught me in a relevant subject is somewhat limited.
One professor in particular I have had many classes with, and I did well in most of them. However, in my most recent class with him (last semester) I did fairly poorly. I was often behind on assignments, and while I was in communication with him and tried to work with him to catch up, he would often say things like "you probably just need to study a bit more, this material shouldn't be too hard."
There is probably some good in this. Since I did well in his classes in the past, he may be confident in my abilities and thought that I should be able to keep up in this class. This could also mean that he thought I really wasn't trying very hard. This is probably true to some extent, as I was having some personal issues last semester.
So with that said, I still felt like I had overall positive experiences with him throughout my college career, and like I said, my options were somewhat limited anyway, so I decided to ask him. I figured that if he was unhappy enough with how I did in his class last semester, he would just decline outright, or say that he couldn't honestly write an overwhelmingly positive letter.
However, he did end up accepting, so all should be well, right? Maybe I am just being paranoid, but I am kind of concerned for a few reasons. One, other professors who accepted clarified that they were willing to write a "strong" letter of recommendation for me, whereas the professor in question did not.
Another reason is the fact that I do believe he will have positive things to say about me, even if there might be some negative mixed in there. So it might be that he considers what he has to say about me positive enough to write a letter, even if it isn't all amazing.
In my research, I found this question: Should I take a "positive, but not enthusiastically strong" letter of recommendation?
So I'm concerned his letter may fall into that category of "positive but not enthusiastically strong", which, as the answers to that question point out, is generally not a good thing to have.
The last factor is that since this is such a small school, he may know that my options are kind of limited, and figures that I pretty much need his letter, even if it's not extremely positive.
Am I just being paranoid? Is it a bad idea to ask him about this?
EDIT: I was reading through more posts on this site and came across this: Difficult student would dispute every grade in the course and now wants letter of recommendation. It was a question asked by a professor, and some answerers mentioned that the OP made no promise to write a strong letter of recommendation, so they were not obligated to, despite accepting to write one. This is kind of worrisome to me, as it's clearly not implicit in acceptation to write a letter of recommendation that you are willing to write a very strong one.