Genesis 38:2

that Jehudah saw there the daughter of a merchant man whose name was Shuva, and he proselyted her, and entered with her.

A DAUGHTER OF A CERTAIN CANAANITE. [In translating “Canaanite,” Onkelos said “merchant.” That is to say, a merchantman who came to dwell in the land of Canaan for business reasons. His intent is to say that Jacob’s sons guarded themselves from marrying Canaanitish women, as Isaac and Abraham, their fathers, had commanded. And thus did the Sages mention in the Gemara of Tractate Pesachim. They took as wives women from Egypt, Ammon, Moab, and from the noble families of the children of Ishmael and the sons of Keturah. It is for this reason that Scripture singles out Shaul, the son of Simeon, as the son of a Canaanitish woman, as he was the only one among them. And even there the Rabbis expounded that the reference is to Dinah who had relations with a Canaanite [Shechem].
Our Rabbis, however, have differed in this matter. Thus they have said:, 84:19. “Rabbi Yehudah says, ‘Twin sisters were born with each of Jacob’s sons, and they took them as wives.’ Rabbi Nechemyah says, ‘Their wives were Canaanitish women.’” It is possible that Rabbi Nechemyah was not particular about [ the term “Canaanitish” and did not mean it to indicate] their genealogy. He meant to say only that they took women from the land of Canaan as wives. However, they were from among the strangers and the sojourners who had come there from all lands, either Ammonite or Moabite women, and other peoples. His purpose was only to differ with Rabbi Yehudah and say that they did not marry their sisters, since a maternal sister is forbidden to the sons of Noah. But according to Rabbi Yehudah it will be necessary to say that the sons of Leah married the twin sisters of the six other brothers, (sons of Noah). Consequently they could marry a paternal sister but not a maternal sister. See Sanhedrin 58 a; Rambam, Hilchoth Melachim 9:5. and they in turn wed the twin sisters of the sons of Leah. It may be that Rabbi Nechemyah does not at all admit the existence of these twins, with Jacob not having any daughter other than Dinah, as the literal interpretation of Scripture would indicate.
It is not logically correct to say that they all married Canaanitish women since there would then have been descendants of Canaan, the accursed servant, among those who inherited the land, just as there were representatives of the seed of Abraham, and Scripture has commanded that he be destroyed until neither remnant nor survivor remain.
In any case, this man [the Canaanite referred to here] was a …

כנעני, a merchant, as per Onkelos. The word appears in that sense both in Isaiah 23,8 כנעניה נכבדי ארץ, “as its merchants, the land’s nobles.” The word כנעני also occurs in this sense in Hoseah 12,8 כנען בידו מאזני מרמה, “a trader who uses false weights.” The word cannot refer to the local Canaanite inhabitants as the sons of Yaakov were very careful not to intermarry with these people.

בת איש כנעני, we do not know why the woman’s name has not been mentioned although the Torah revealed the name of her father. Her father was a merchant, a resident stranger, an export-import merchant, not a member of one of the local tribes. The sons of Yaakov were very careful in avoiding intermarriage with the local population, and when one of them did so, Shimon, his son Sha-ul is mentioned in a derogatory fashion as the “son of Canaanite” in 46,10. This critical comment on Shimon’s wife sets him apart from all of his brothers.

ויקחה, he first legally married her before having marital relations with her, i.e. ויבא אליה.

וירא, it appears that she was very attractive physically and therefore appeared to him as an appropriate mate.