あなただけが頼りなのです。

you (referring to someone of equal or lower status); dear (what a wife calls a husband)

only; just; merely; simply; no more than; nothing but; alone; as (e.g. as soon as, as much as); worth

indicates sentence subject (occasionally object); indicates possessive (esp. in literary expressions); but; however; still; and

reliance; dependence

indicates possessive; nominalizes verbs and adjectives; substitutes for "ga" in subordinate phrases; (at sentence-end, falling tone) indicates a confident conclusion; (at sentence-end) indicates emotional emphasis; (at sentence-end, rising tone) indicates question

be; is