What is a quotation from Dracula that illustrates his personality traits?
I like "Enter freely and of your own free will" to Jonathan Harker as he enters Castle Dracula for the first time. Although he is being hospitable, he is inviting Jonathan to more than a business dealing. Jonathan's entering of his own free will, albeit naively, demonstrates that many vampire victims willingly submit to the power of the vampire. They become tantalized or hypnotized, suggesting the seductive manipulations that cause the victim to willingly expose his/her throat. Arthur Holmwood is temporarily hypnotized by Lucy's invitations to "kiss" her until Van Helsing pulls him away, much to Lucy's displeasure. Mina Harker is also hypnotized by Dracula's spell as he opens a vein in his chest to allow her to drink. A vampire cannot enter a place where he has not been invited, hence Dracula's using Renfield as an opportunity to get into the asylum that is housing Mina for safety. The notion of invitation and free will begins with Dracula's greeting to Jonathan.
One nice quotation shows what other people thought of Dracula.
When I asked him if he knew Count Dracula, and could tell me anything of his castle, both he and his wife crossed themselves, and, saying that they knew nothing at all, simply refused to speak further. (ch 1, p. 5)
It is clear that while Dracula seems like a perfectly nice gentleman in his note, the people are afraid of him and will not even talk about him. This shows you that he is trying to present himself as normal, but clearly locals do not see him that way.
The "What blood runs through these veins" speech shows us Dracula as a warrior (or a killer, depending on your viewpoint). He is boasting in front of Harker suggests something darker. The scenes later, where he is playing the role of host, is undercut with a sense of menace as he (subtly) tells Harker he won't let him leave.