Sunny, thank you is a proper answer. If you say thank you, your intention is to acknowledge her praise. That's all that is within your control. Your intention was positive, your speech was positive. And whoever praises you shall recognizes that and that's it. Anything which the other person thinks once you say, "Thank you" is outside of your control. So when you go to bed, you know that your intention was positive and that your speech was positive, that you acknowledged the person's praise, and you can go to sleep in peace knowing you did your part. I hope that helps.

Well, I think that "thank you" is probably good enough. If you want to be a bit more emphatic, you could say "thank you, that's very kind" or "that's very kind of you to say so". Without knowing what your relationship is like, it's difficult to judge.

Thanks for your answer. I'd like to know some response that is more casual.

you could say for example : "really I'm so happy hearing that it's really motivating Thank you so much "