During a conversation if you agree with someone, you could use one of the following expressions. I agree with you one/a hundred percent. I (completely / really / totally / absolutely / honestly / truly) agree with you (on that) You’re (completely / totally / absolutely) right. That’s (so / completely / absolutely / undeniably) true. I agree with you entirely. I couldn't agree with you more. I share your opinion. I share your view. I couldn’t agree more. That's exactly how I feel. Exactly. I'm afraid I agree with John. I'm with …
You're welcome. (Most common and perfectly alright) But this is a bit overused expression. To bring variety into your conversation you can try other options You're very welcome. You're most welcome. (formal) You're quite welcome. You're so welcome. (Response to "Thank you so much.") Example Thank you so much for giving me the lift. Oh! You're very welcome. No problem! (More American) (Too casual, better to avoid) No worries! No issues! Not a problem! No big deal! It's OK! It is/was no bother Example Than…