It's all a matter of Perception.
If you, as Uke, are giving a commited attack with strong intention and will... not ill will and meaning of harm, then it is up to the Nage to do their job and execute good technique.
If you, as Nage, are perceving harmful intent on the mat, then it is one of two things: you have a "partner" who doesn't fully grasp what their job as Uke is (not likely if your sensei is doing his/her job) OR... you as Nage are misinterpreting the intent and taking it personally... which you have no buisness doing as you have a TECHNIQUE you should be doing in spite of it all!
If someone as Nage is feeling threatened during practice, that person has an issue or issues to deal with.
If someone as an Uke is meaning to hurt their training partner and actually have the intention of not just attacking but doing actual harm (despite this being practice) then again, that Uke has issues and should be talked to by the instructor.
Personal feelings should be left off the mat
. Then... and only then, you will know that this intent and serious attack coming at you is actual PRACTICE to prepare you for the real thing.
Take it as a compliment! If they are coming at you full-tilt-boogy with 110% intention to strike, then they obviously feel you are capable of dealing with it and executing good technique and dissipating the energy! "Good on ya, mate!" as the Aussies would say.
PS: I'm no Saint. I'm still working on all of the above and have been for the last several years. It's an on-going process.