Yes — "is" is always capitalized in title case because it is a verb.
"Is" is a verb — specifically the third person singular present tense of "to be" — and verbs are always capitalized in title case. It is capitalized in AP Style, Chicago Style, MLA Style, NYT Style, AMA Style, and Billboard Style.
Writers sometimes assume that short words like "is" should be lowercase because other short words like "in" and "the" are lowercased. The distinction is grammatical category, not word length. "Is" is a verb and is always capitalized.
APA Style, Wikipedia Style, and Sentence Case use sentence case rather than title case. In those styles, "is" is lowercase unless it is the first word of the title.
A title like "Love Is Blind" correctly capitalizes "Is" in AP Style, Chicago Style, and MLA Style. Writers who lowercase it — a common error — are likely applying preposition rules to a verb.
"Is" is a verb, and every title case style guide capitalizes verbs. The rule is consistent across AP Style, Chicago Style, MLA Style, NYT Style, and AMA Style: verbs are principal words and receive capital letters regardless of how short they are.